this is bbc news — i'm lukwesa burak. the headlines: elaine thompson—herah ofjamaica has won the women's 100—metres final in tokyo. earlier, there was heartbreak for team gb sprinter, dina asher—smith, who had to withdraw from the games through injury. before that, there was gold and a world record for team gb in the 4x100 metres mixed medley final. team work makes dream work — and another gold in the triathlon mixed relay event, and finally a first gold medal

forjonny brownlee at his third olympic games. and, this is austin halewood at the bbc sports desk — i'll have all the news on the medals, the records and the upsets in tokyo. afghan security forces are battling to defend three key cities from advances by the taliban — reports say militants have breached front lines in herat. medical experts are warning that an oxygen monitoring device, called an oximeter, works less well for people with darker skin tones. bbc news understands the government is no longer considering making it compulsory for students to be fully—vaccinated to attend lectures in england. and coming up later this hour — click takes a trip to iceland.

good afternoon and welcome to bbc news. jamaica has secured a clean sweep — first, second and third — in the women's 100 meters this afternoon at the olympic games in tokyo. it comes as one of team gb�*s great medal hopes — dina asher—smith — saw her bid for the podium come to an early end, afterfailing to qualify for the 100 metre final. she says she's still struggling with a hamstring issue, and has now withdrawn from the 200 metre event. earlier today, team gb added two more gold medals to their tally. the first came in the inaugural triathlon mixed relay. then, in the swimming pool, great britain claimed another, this time, in the mixed 4x100 metre medley.

so where does that leave the medal table? well, team gb remain sixth — they've picked up eight gold medals and 28 in total. at the top is china with 21 golds and 46 overall. for a full round—up of the action at the olympics this morning — let's cross to austin halewood at the bbc sport centre. good afternoon. what a final of the women's 100 metres it was. jamaica's elaine thompson—herah ran the second—fastest time in history to succesfully defend her 0lympic 100 metres title. she beat her compatriot shelley—anne fraser—pryce with a time of 10.61 — the second—fastest time in history, just 12—hundredths of a seconds short of the world record set 33 years ago by american florence griffith—joyner. shericka jackson completed a jamaican one—two—three in tokyo. britain's deryl neita finished eigth in the final.

there were great hopes for britain's dina asher—smith in the 100 meters, but she failed to reach the final, after revealing that she'd been struggling with a hamstring injury. she's even had to pull out of her stronger event, the 200 metres — and she was understandably emotional as she explained her decision. i am going to pull out. john just had that conversation with me, and that's the one that... as reigning world champion, you just... and i was in such good shape. you just know that the olympic champion is not too much of a further step. i'm really proud to have been able to execute my races here today, really proud everything i have done to this point. but when you're talking about the standard that i want to be at and i know i am capable of, sometimes if you... there's plenty more championships for me to come and kill.

and in the men's100 metres heats, european champion zharnel hughes ran a season's best time of 10.04, to reach the semi—finals along with team—mate cj ujah and reece prescod. away from the athletics, it's already been a golden saturday for team gb in tokyo — and it's been a day when team work has been the key to success. firstly, in the new triathlon relay, and then after that back in the pool — where the british team are enjoying their most successful games in over a century. adam wild reports. the triathlon will be golden for great britain! it's the mixed medley relay, great britain win the gold by miles! for all the individual brilliance, in tokyo today it was teamwork that triumphed. super saturday had barely begun, but team gb was already looking at four new 0lympic champions in this, the inaugural triathlon relay. jessica learmonth led the way for britain, then the turn ofjonny brownlee. individual bronze in london, silver in rio, this his final 0lympic race,

a last chance to complete the set. georgia taylor—brown had given britain a 21—second advantage, and although alex yee was dramatically caught for a moment, when it came to the finish, he and gb were in a class of their own. he will win the gold. four new british olympic champions before breakfast. forjonny brownlee, gold at last. the olympics, i've completed it! i've been waiting for that one. yeah, it feels absolutely amazing. third olympics, and to finally walk away with olympic gold, and we did everything we possibly could. whilst over in the pool, team gb have surpassed expectations. now a moment for the team's finest to come together. the mixed medley relay, another new 0lympic event. in the company of the finest swimmers on earth, britain have already proved they can excel. here, they were doing it again. kathleen dawson gave way to the peerless adam peaty.

he did what he always seems to do, before james guy powered britain into the narrowest of leads. and here was anna hopkin in the final leg. great britain are going to win their fourth gold in the swimming pool! one word that has changed the whole team is belief. we've got champions who believe we can win, champions who believe we can get world records, and if you've got one belief, you can build everything around that. two team relays, two olympic team titles — another golden day for team gb. emma wilson has taken windsurfing bronze on her 0lympic debut. she was already guaranteed a medal going into the final, after winning four of her 12 races, and she crossed the finish line in second place — but with cumulative scores counting, that gave her bronze, behind china's lu yunxiu and the rio champion, charline picon of france. that's all the sport for now, but there's lots more on the bbc sport website,

including the start of the football league season in scotland and the build—up to the second lions test against south africa this afternoon. well, our reporter, eleanor roper, is at the lee valley athletics centre in north london. she says this is really disappointing news for dina. not what she wanted or anyone expected. we have been watching here on the big screen, really exciting. desiree henry is here, she raced with dina at rio. give us your reaction. i'm kind of shocked, but i made this prediction yesterday when i said people should not count out elaine thompson—herah, she is the previous olympic champion. that does not come lightly. i am just shocked how she did it, and at the time, 10.61 is absolutely incredible. she did it in class and style.

you did call it. ijust cannot believe it. but we all hope and want our favourites to win, but for them to go out and do it it is a whole other ball game. also, it was a jamaican one, two, three, which i expected but did not expect it to see it live. hugely disappointing for dina asher—smith, but deryl made it through to the final? i thought for daryl, this is still an amazing thing to be celebrated. she made an olympic final. yes, it may not have been the performance that she wanted, but she should still be able to hold her head up high. congrats to deryl also. huge disappointment

for dina asher smith, she has been struggling with a hamstring injury, she has also pulled out of the 200. can you just talk us through how disappointing that will be for her? this will be extremely disappointing. you know the fact that she came down to the olympics and try to compete in every single round possible, you knew that her mind frame was in a mindset of let's see what my body can do and if it can hold up. unfortunately, it was not the case and i am just extremely sad for her because i know she was on a quest of coming back with olympic medals in multiple events and it has not worked out. all she can do is keep your head up, the world championships are next year, there are so many championship. this is not the end for her. definitely not, showing her class again today, very quick to congratulate her team—mate on that 100 metres final. next up we have the men's. an investigation has been launched after the body of a five—year—old boy was recovered from a river, in south wales. officers were called to the scene near pandy park in the village of sam, near bridgend at 5:45 this morning.

police have appealed for information from anyone who was in the area at the time. afghan security forces are battling to defend three key cities from advances by the taliban. reports from herat, in western afghanistan, said the militants had broken through front lines — but a local official said government forces were moving cautiously to try to avoid civilian casualties. fighting is also continuing in kandahar and lashkar gah in the south. hundreds of people are reported to be fleeing their homes. secunder kermani has just sent this update from kabul. fighting is taking place in and around a number of afghan cities. in lashkar gah, in the southern province of helmand, taliban forces came within one kilometre of the governor's office right in the centre of the city yesterday before being pushed back. the afghan army commander there saying his troops managed to inflict a high number of casualties on the militants,

but we understand they remain at the mostjust a few kilometres away from the city centre. today in lashkar gah a hospital was badly damaged by government air strikes targeting taliban fighters in the area. i'm told at least one security guard was killed and two doctors injured, though initial reports suggested that patients being treated at the hospital had already been evacuated. in the west of the country, in the city of herat, fighting is ongoing for the third day after government forces managed to recapture the area around the airport, which had been briefly taken by the taliban. government forces there supported overnight by us air strikes and by militia forces led by a powerful veteran commander in his 70s. it seems pretty clear that the taliban having already captured large amounts of rural territory in afghanistan are now really turning their focus to the country's cities. they haven't yet managed to capture one, but this fighting is of course displacing tens of thousands of people. many other afghans are planning, or at least considering,

their options to leave the country. many people fear that come the end of august and the formal end of international military mission in afghanistan, the violence is only going to get even worse. our chief international correspondent, lyse doucet, has been speaking to the eu's envoy for afghanistan, tomas niklasson, in kabul, on how serious this moment is. the best realistic scenario is one where the taliban offensive is held back. where there is a bit of push back, a bit of rebalance. all these nice words that still mean further suffering and deaths, a larger number of afghans dying on both sides. more people on the run, leaving their homes. but with this recalibration, rebalancing, the taliban would then, after some time, be ready to come back to negotiations in doha or start negotiations in doha in earnest, to find a negotiated solution to afghanistan's problems.

earlier, i spoke to our chief international corrspondent, lyse doucet, about who is coordinating the taliban's military strategy. many are asking this question — who is the brilliant military mind behind this strategy? to start, the taliban started their events in the district, not in southern afghanistan, their traditional strongholds, but they began in the north, putting on the back foot some of the militias there, some of the local forces there, and made quick and easy gains. then they went after the border crossings on pakistan and the northern borders and the western border with iraq, seizing the strategic crossings, which lent put further pressure on the cities. that gave them important sources of revenues. the first strategic capital in which

they advance was kandahar, the ancient capital of afghanistan. that has long been a saying in afghanistan that whoever controls kandahar controls the country. many have been asking if it is the taliban coming up with this strategy. is it neighbouring pakistan who has always played a key role in supporting the taliban? we do know they have been going there for a century, hospital support, many taliban leaders are based there. it is a growing sense that someone is behind this strategy, which has really given the taliban an edge in these early stages of a taliban advance and taliban offensive. american military forces are said to have boarded an israeli—operated oil tanker after a british and romanian member of crew were killed by a reported drone strike. an israeli government minister has accused iran of exporting terrorism in the wake of the alleged attack off the coast of oman.

the headlines on bbc news: elaine thompson—herah ofjamaica has won the women's 100 metre final at the tokyo games — in a new olympic record time of 10.61 seconds. afghan security forces are battling to defend three key cities from advances by the taliban — reports say militants have breached frontlines in herat. medical experts are warning that an oxygen monitoring device, called an oximeter, works less well for people with darker skin tones. medical experts are warning that an oxygen monitoring device, called an oximeter, works less well for people with darker skin tones.

i'm going to discuss the subject further with a doctor who is part of the author of the study that is highlighting this issue. thank you forjoining us on bbc news. first off, just how serious is this? is a very serious _ off, just how serious is this? is a very serious issue _ off, just how serious is this? is —. very serious issue and i'm very glad that it very serious issue and i'm very glad thatitis very serious issue and i'm very glad that it is getting the awareness that it is getting the awareness that it is getting the awareness that it requires. when considering the use of these devices, how widely accessible they are to patients and how frequently they are in the clinical environments, in hospitals and gps, it is really important that both patients, members of the public and clinicians are aware that the readings can be less accurate and darker skinned patients.-

readings can be less accurate and darker skinned patients. which way are the result _ darker skinned patients. which way are the result skewed, _ darker skinned patients. which way are the result skewed, lower - darker skinned patients. which way are the result skewed, lower or- are the result skewed, lower or higher? are the result skewed, lower or hi . her? are the result skewed, lower or hiuher? . , ., are the result skewed, lower or hiuher? . _, ., , higher? the devices are actually likel to higher? the devices are actually likely to overestimate _ higher? the devices are actually likely to overestimate oxygen i likely to overestimate oxygen saturation is, particularly in black patients as well as other ethnic minority groups. many white patients of a particular study conducted in america found that black patients were three times more likely to have that oxygen saturation reading overestimated in comparison to white patients. overestimated in comparison to white atients. ., , ., ,., ., patients. there was a report that was conducted _ patients. there was a report that was conducted at _ patients. there was a report that was conducted at the _ patients. there was a report that was conducted at the end - patients. there was a report that was conducted at the end of- patients. there was a report that| was conducted at the end of 2020 patients. there was a report that. was conducted at the end of 2020 in america, and this was highlighted, because a lot of people have these oximeters at home to monitor themselves if they have contacted covid—19. howeverthere themselves if they have contacted covid—19. however there was a report backin covid—19. however there was a report back in in 2007 that highlighted the issue with people with darker skin. why has this not been picked up, change, fixed? that why has this not been picked up, change. fixed?— why has this not been picked up, change, fixed? that is a question for all of us- _ change, fixed? that is a question for all of us. we _ change, fixed? that is a question for all of us. we are _ change, fixed? that is a question for all of us. we are hoping - change, fixed? that is a question for all of us. we are hoping that i change, fixed? that is a question | for all of us. we are hoping that as

the pandemic has shone a light on inequalities as well as a disproportionate impact on ethnic minority groups, it is very important that... even though it was mentioned a few years ago, their most recently had a larger population that was supporting the two. when we consider the intact of this, this can contribute whether or not people come into hospital, how soon they come into hospital, what kit is provided when they do come into hospital. the fact that if your oxygen readings are overestimated, that means you are likely to have a lower reading, are you receiving the oxygen that is necessary to adequately treat the patient at that time? if these patients are admitted to intensive care units, are they receiving the treatment that they require? of course this can have a significant impact on health outcomes. unfortunately at the pandemic has provided a suitable

opening to further explore this area. . . opening to further explore this area. ., ., ., area. our rear fairing to the seriousness _ area. our rear fairing to the seriousness of _ area. our rear fairing to the seriousness of this - area. our rear fairing to the seriousness of this being i area. our rear fairing to the - seriousness of this being primarily in home settings and people who are monitoring their own oxygen? or in hospital settings as well? you would hope they would have slightly more sophisticated equipment to monitor people with darker skin if they know this is an issue. i people with darker skin if they know this is an issue.— this is an issue. i think it is important _ this is an issue. i think it is important in _ this is an issue. i think it is important in both - this is an issue. i think it is - important in both environments. of course in a hospital there is additional medical equipment that they can use to check more accurately oxygen saturation is. however, what we need to make sure it is that the health care workers are very much aware of this difference in outcomes in the readings of darker skinned patients. in that regard, that they are able to figure out whether or not they require other testing and a much more prompt manner. also because of them for patients and members of the public at home. of course in the pandemic a lot of people were self monitoring, it was very easy to

order a pulse oximeter online. i'm very pleased that the nhs has supported making sure that there is an appropriate information made available for patients, knowing that it is notjust reliable to look at just a single reading, but looking at age ten. are your oxygen saturation levels going down? also knowing it if it is less accurate in my skin tone, or a loved one who is unwell, that might mean the patient has to go into hospital a lot more surround than previously anticipated.— surround than previously anticiated. , ., _ anticipated. obviously raising awareness — anticipated. obviously raising awareness is _ anticipated. obviously raising awareness is key. _ anticipated. obviously raising awareness is key. i— anticipated. obviously raising awareness is key. i am - anticipated. obviously raising awareness is key. i am a - anticipated. obviously raising i awareness is key. i am a person anticipated. obviously raising - awareness is key. i am a person of a darker skin tone. i had never heard of this issue, so it's great to know. before we talk about what people should be doing and how difficult or easy it is to question medical professionals, just quickly explain to us why. i know you can get these results with your skin tone, if you are wearing dark nail polish, if you have got cold skin? there are a number of things that

can contribute to potential errors in these devices. fortunately, they are available online. however i think the concern when it came to skin tone isjustified of think the concern when it came to skin tone is justified of how many people might be affected in this regard. also considering the fact that you can take off your nail polish on one of a patient, but you cannot really alter a person's skin tone. awareness is always the first step. there are certain actions i believe that should be taken as a result, including reviewing other medical devices that may be influenced by a person's skin tone. it is not to say that all devices will be influenced by a person's skin tone, and is also not to say that these devices are not useful because they very much our. it is making a culturally appropriate and sensitive to diverse groups. i5 making a culturally appropriate and sensitive to diverse groups. is it auoin to sensitive to diverse groups. is it going to be _ sensitive to diverse groups. is it going to be that _ sensitive to diverse groups. is it going to be that difficult effects? basically, the thinking behind it is it is all to do if this light

absorption through something darker, basically. in order to fix it, just how difficult is that? i basically. in order to fix it, 'ust how difficult is that?* basically. in order to fix it, 'ust how difficult is that? i think there is such a great — how difficult is that? i think there is such a great need _ how difficult is that? i think there is such a great need for— how difficult is that? i think there is such a great need for further. is such a great need for further research into this area, just to support further adaptations that might be made to the devices, for example, if we're to include a calibration option. so a patient can select their skin tone on their device or the device can assess a patient�*s skin tone and adapt accordingly. that is definitely going to require greater research with larger populations and diverse groups. unfortunately in the research sphere, that can be quite difficult, given perceptions towards research and engagement of ethnic minority groups. however of course we discussed the fact that awareness is very important, but when looking at the adaptations of these devices it may potentially take longer than we would have hoped.— it may potentially take longer than we would have hoped. doctor, you are very approachable. — we would have hoped. doctor, you are very approachable, but _ we would have hoped. doctor, you are very approachable, but some - we would have hoped. doctor, you are very approachable, but some people l very approachable, but some people would be terrified to question their

doctors or nurses. our medical professionals aware of this? i hope as this review _ professionals aware of this? i hope as this review is _ professionals aware of this? i hope as this review is released - professionals aware of this? i hope as this review is released a - professionals aware of this? i hope as this review is released a few- as this review is released a few months ago, more and more health care professionals, as well as doctors, are aware of this. however in conversations i have had, a lot of my cogs are not aware of this. that shows there is only for patients to be more adequately informed, but also in need of health care professionals to be informed. —— a lot of my colleagues are not aware of this. the way it is received is so important by the clinician serving a patient, that may result on them deciding on another occasion to come into hospital soon out in comparison to waiting at home and waiting for their condition to worsen significantly. i think it is very important that when concerns are raised by patients that health care professionals are receptive to these concerns and also take the opportunity to inform themselves and their colleagues as well of this

difference. their colleagues as well of this difference-— their colleagues as well of this difference. ., ., ,, ., difference. doctor, thank you for our time difference. doctor, thank you for your time here _ difference. doctor, thank you for your time here on _ difference. doctor, thank you for your time here on bbc _ difference. doctor, thank you for your time here on bbc news - difference. doctor, thank you for i your time here on bbc news today. bbc news has been told that the government is no longer considering making it compulsory for students to be fully vaccinated against coronavirus to attend lectures in england. ministers had previously refused to rule out a requirement to be double—jabbed on university campuses, and said the decision would be taken in september. our political correspondent, pete saull, says this comes in the context of the controversial decision to consider so called vaccine passports in other areas. from the end of september, if you want into a nightclub, it will be a question of if you're notjabbed, or double—jabbed, you're not coming in. but ministers have been floating other settings where that might be the case. opening up international travel for people who have had both jabs. the idea was that once university students return from their summer break in the autumn, they will have to have both jabs to go to lectures or even stay in halls of residence.

that was something they were looking at but i do understand that particular proposal has been shelved. meanwhile conversations about other things, premier league football, for example, continues. why did they go back on that proposal then? i think they were two key reasons. the first being logistics, how could universities police this? there were legal questions as well. when you get an offer of an university place, that is considered to be legally binding. i think ministers are also aware that unease is growing on conservative backbenchers about this wider issue of vaccine passports. jacob rees—mogg last night said it would not be the end of the world to have to show proof of vaccination to gain entry to venues, but he also said we should protect our ancient freedoms. i think that sentiment about freedom is one shared very widely across the conservative party,

and i sense a lot of people out there might be uneasy about having to show papers to get into anywhere, whether it be the pub, nightclub, restaurants, whatever. i think the government now feeling the heat on this issue and might ultimately decide the use of vaccine passports might not be as widespread as it was a couple of months ago. have they laid an alternative to the return to university for students? not specifically. initially, they say that this would not be about covid certification in september. testing will clearly play a part of the mix as well. it is hoped by that stage, case numbers will be down and hopefully things will start to return to normal. the uk telecommunications industry hopes a satellite that has gone into orbit will help maintain its global leadership in the sector. a quarter of the world's big telecoms spacecraft are manufactured in britain, and the new quantum platform is billed as the market's next—generation product. quantum was launched on an ariane rocket

from french guiana last night. here's our science correspondent, jonathan amos. another rocket climbs skyward to bolster a sector that europe, and the uk in particular, has come to dominate — the business of telecommunications satellites. there are hundreds of these spacecraft overhead — bouncing tv, phone calls, broadband and other data services around the planet. but the new satellite going into orbit, called quantum, represents a big step forward in technology. while traditional telecom spacecraft are configured before launch to do very specific tasks, quantum has been built for flexibility. it is the sector's first fully reprogrammable spacecraft. it is able to rapidly change the coverage, bandwidth, power and frequency of its signals. one of its uses will be for disaster response, providing emergency communications to the teams that are sent to help people in places hit by catastrophic

floods or earthquakes. quantum's manufacturers in the uk, that is airbus and surrey satellite technology ltd, will incorporate the prototype's technology into their future spacecraft, hoping to maintain their world leading status in what has become a highly competitive field. jonathan amos, bbc news. more than 60 million americans across the pacific north—west and the us south—east are facing another record heatwave with forecasters predicting temperatures could climb to a0 degrees celsius in washington. records were shattered across the regions last month when a days—long heatwave killed hundreds of people. a study published earlier this month found that the devastating heatwave would have been "virtually impossible" without the impact of climate change. now it's time for a look at the weather with louise lear.

good afternoon. it is sunny spells and scattered showers for many of us for the remainder of the afternoon. let's take a look at what has been happening. quite a lot of cloud, generally, across the country. showers have been sitting through eastern scotland and north—east england and more widespread showers through central and southern wales down into central and southern england as well. here, the odd rumble of thunder but with some sunshine we could see temperatures peaking at 21 celsius, a little bit cooler further north. and that cooler air is set to descend steadily south. behind it, this cold front. that is going to continue to enhance some showers for sunday across southern parts of england, in particular. some of those showers, as the isobars open up, the winds fall lighter, and they could be heavy and slow moving, still with the odd rumble of thunder. so, that is going to be an issue across central and southern england. behind it, sunny spells, fewer showers, but not as warm as it has been of late. top temperatures, 12 to 21 degrees.

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