mexican authorities have promised that an investigation into the matter over past collapse will be open and independent. at least 2a people were killed and almost 80 injured when a train plunged into the road below. rescue efforts are still under way. derek chauvin, the white former police officer convicted last month of the black man george floyd has requested a new trial. his legal team alleges misconduct by prosecutors and jurors and say the process was not impartial because of pre—trial publicity. pressure is mounting on india �*s element to impose a national lockdown as a country official records more than 20 million covid infections as the health system struggles to cope.

now on bbc news, click. this week: how to uncover deadly secrets online. the secret codes attracting more women into cybersecurity. and tenet, the oscar—winning secrets of making time to backwards. audio tracks backwards. welcome to click. we all know how easy it is to fake things online these days, not even photos, voiced or videos are safe, as we well know, right? yes, we've worn fake clothes, we have faked our voices with software. i've even been entirely

faked with a virtual me — although i am convinced that she looked ten years older. i whole—heartedly agree. later in the program, we're going to see the hollywood version of this, when we look behind the scenes at the film, tenet. spoiler alert — it wasn't all real. but these days, you don't need a big budget to do this. just think of those zoom backgrounds that we've all been looking at. admittedly, the edges of your hair do often give the game away, but these pictures are pretty good, a lot better than we would have imagined they could be five years ago. (harp glissando) so, check out the next advancements. this is where zoom can put meeting participants into a meeting room, a real one that's not real, although i think something has gone wrong with the sizing here, don't you! my seat�*s way too low and you're far too small. there's a variety of scenes. do you want to meet me for a coffee? look, here we are in a coffee shop. yeah, i will have a latte, please. i'd say this is cute but does it make you feel like we're in the same room, really? no, i still feel like

we're on a zoom call. maybe this is one for the audience, rather than the participants. and while there is plenty of fakery around, the truth is out there, as a certain fox once said, and there are some people who know where to look. the internet is just such a vast place, and like there's so much out there that's just public, so many ways that information can be manipulated. and even, like, political news can be manipulated in someone�*s favour, so that is where i think open source intelligence is useful. 18—year—old computer science student kenyon lee has gone viral on tiktok by using so—called open source intelligence, collecting and analysing publicly available data. his main trick — he uses objects in a shot to guess heights. woman: how tall is spencer? now, kenyon did do this test on a video of me that he found online and we'll come

back to that later. mainly on account of it being the most embarrassing video i've ever posted online. but we have some serious stuff to talk about first. look, trust me on this. there are groups of people out there who are using open source intelligence techniques to do much more serious detective work. these are anatoliy chepiga and alexander mishkin, widely believed to have been responsible for the salisbury poisonings in 2018. this week, a collective of open source intelligence investigators revealed they'd also managed to link to these two men to the bombing of a czech ammunition depot four years previously. that collective is bellingcat, and we've met its founder, eliot higgins, before. in 2014, it was just him, now he has a foundation in the netherlands, 20 staff members, and a growing network of volunteers all across the world. i caught up with eliot again recently and he told me that flight logs of chepiga and mishkin�*s trip to the uk

in 2018 were revealed by a russian news site, and that showed that their passport numbers were only a few digits apart, which was to say the least, unusual. that caught the interest of bellingcat, in particular our investigator christo grozev. so, christo looked at these databases and discovered these two individuals didn't exist before 2012. theyjust popped into existence in these databases in 2013, which was suspicious. he then approached basically an information broker who sold him these domestic passport registration documents, and stamped on them was the number of the russian ministry of defence. and it became clear they were not ordinary people, that these appeared to be russian intelligence officers. bellingcat�*s investigation didn't end there. their evidence showed that scientists linked to the 2018 poisonings were following russian opposition leader, alexei navalny on a0

separate trips in 2020. that includes the journey where he was poisoned. it seems that the site we stumbled on with the skripal story, is this entire kind of network of russian assassinations using nerve agents. and that sounds completely insane, but, you know, we have the receipts. we have the phone records. we have everything to show this is happening. and this is basically unique to russia because russia has this acute, massive amount of corruption where data, phone records, even if they are spies�* are freely available to anyone that does a bit of googling. what tools or software do you or your investigators use when you're looking at photographs and trying to work out where they've been taken and when you are tracking information back into the internet? we have an online tool box, which is basically loads of links that anyone can go and look at and use them themselves. probably one of the most powerful tools is google, google earth, google streetview. they are extremely useful.

resources now allow you to track aircraft, like flightradar, marine traffic allowing you to track vessels. photographs and videos can out very convincingly be doctored, does that cause you a problem, or is that a new investigative stream for you ? you have concern about deep face and there is concern on social media about things being retweeted. we approach stuff as evidence so when we look at that kind of thing, we say, here is a video of tom cruise can we find out the golf course? or if someone is giving a speech, it is going to be from a longer piece of media. people don't give two minute on 20 seconds speeches. they are usually longer. so we look for that original footage. we look at the account

who shared it. is it shared by an official news organisation? we look at the account behind it. have they shared things before? what has that stuff been? you look at the different dimensions of that video both inside the video and how it has been shared and propagated online. absolutely fascinating stuff. that was elliott higgins. right, i cannot put this off any longer. it is time to go back to kenyon lee. the tiktok person who guessed your height? the video he chose was my ice bucket challenge from years ago — which, if you have not seen, well, you are probably one of the lucky ones. i have seen it. and i can't unsee it. ijust can't get enough of you. i was trying to raise money for a good cause so i decided to go full outrageous

and i kind of forgot that the internet never forgets. ok, here it comes. i decided to look at the ice bucket challenge. i marked the top of his head and scaled his height using the bucket. this translate to about 174 and three quarter centimetres. there was a point to all of this. did he get your height right? he said 174.75. let's have a look. oh, wow, 175! not bad, not bad at all. not bad considering he did that from the dimensions of a bucket. yes, good job he didn't use a three and a half inch floppy disk. hello, and welcome to the week in tech.

lyft was sold to japanese car firm toyota for $550 million. and tiktok said it would open a european transparency and accountability centre in ireland. the announcement follows concerns over how the chinese social media giant serves its young users. the first triple—drop drone hit the skies. this electric device can carry and deliver three separate loads — although it can only stay in the airfor a maximum of 90 minutes. two college engineers won mit awards for their invention. this remote—controlled robot helps farmers stay safe while it levels and redistributes the crop. it can dig itself out of 5 feet of grain as well. and australian researchers on al labour — this autonomous

arm uses al to identify nearby apples, leaves and branches, all so it can plan the path for its pneumatic suction plucker. it can pick and deposit each apple in as few as seven seconds — how do you like them apples? this is huawei mate x2, the third iteration of its folding phone and easily the best yet. the folding screen is now protected inside the phone when closed, which makes a lot of sense. it has been a pleasure over the last years to be able to try out so many of these folding phones and see this new category of devices emerge and all the manufacturers have had such different approaches. huawei's was always unusual because it wrapped the folding display outside the device which looked super cool but it did leave the display vulnerable. this time they are taking a leaf out of samsung's book.

they have put the folding screen on the inside of the phone where it is protected. they have taken a few leaves. this is very similar to the galaxy z fold2. from the fingerprint reader on the side here to the speaker on the bottom to the camera button and the chunky hinge. i thought folding phone might be the end of every phone looking the same but here we. the mate x2 is a much better design than the original. the screen snaps into place. this is a big improvement. this is the first one of these appeal comfortable enough to throw in my gym bag like i would with my regular telephone. another fantastic bit of engineering. when i first started using it, it felt really comfortable in my hand. i couldn't quite put my finger on why. i've been very scared of dropping these folding phones because they are typically very expensive

and fragile. but, with this one, i never felt like i was going to drop it. it sat comfortably in my hand. and this is why — the phone is wedged—shaped, which moves the centre of gravity closer into your right hand, so when you're holding it here, there is less weight over here. it weighs about 300g, which is more than a regular phone but because of this, it does not feel like it. i also like the outside display because, when it is close, it is a full—size regular smartphone with no compromise. you get pretty the same experience as you would with a regular huawei smartphone, including the great camera array. great stuff. that was chris fox. the secret services have always been secret. but it seems that something is in the world in espionage are changing. m15 has just joined instagram. but other areas have not.

for example, the number of women working in the field stands at just 16%. but a schools competition is hoping to change that. to see the role that women have taken over the years in cybersecurity i first took a trip back in time to look at some pretty special computers and coders that used them. i'm here at the national museum of computing on bletchley park, a place full of computers and memories, not least of the world war ii codebreaking. today, it's largely associated with alan turing, who cracked the previously unbreakable german enigma code. his efforts undoubtedly helped give the allies the edge. but 63% of those working out of bletchley park were in fact women, many of them working

on the world—famous colossus. the job descriptions that they gave to women codebreakers were different from the job descriptions that they gave to men so, if you go and look at the paper records, you will find that women are described as typists or translators or clerical staff. and that disguises what they were actually doing, and this is because men were on a different pay scale, so the codebreakers were on one pay scale and got differentjob titles from the women, who were on a lower pay scale, but it didn't tell you anything about the quality of what they were actually doing all day. what should alan turing's legacy be? i've just written a book called reflections of alan turing which is trying to getaway from this sort of nostalgic, sepia—tinted views of sort of what he was and what he

should stand for. and he was always looking at the future. he was sort of like almost science fiction in, you know, thinking of these sort of amazing things like machine learning, which was sort of obviously completely but while many women were employed in codebreaking then, the imbalance in numbers between men and women in cybersecurity today is huge. well, to help put things right, the national cyber security centre's cyberfirst girls competition is trying to find the next generation of female codebreakers. it involves solving puzzles to do with coding and logic... cryptography, cybersecurity networking. ..and it's really fun. the competition, like, | promotes the idea that girls can code. here i am today. it's officially competition day and i'm very excited. we're going to also give the teams a — some top tips. i in the semifinals, we could seel the leader board and i remember everyone was rushing i

to do more challenges. 12— and 13—year—old girls from across the uk have been competing in this year's challenge, which has moved online. you may think that's where it should be, anyway, but it is a collaborative and creative process. we need to succeed at our mission to keep the uk safe, to keep people who live in the uk safe to work and live online. and we need all kinds of people to do that, just to represent the society that we are working for, but also to get all of those different perspectives, and girls sometimes bring a different perspective. and some would argue that women have a real knack for it. women are good at linguistics, which makes them irreplaceable at any natural language processing services. they are also very attentive to detail and good at pattern recognition and overall, patience, which are requirements for any computer science—related job. with an abundance of all those

qualities, this year's contenders are certainly feeling the pressure, having battled their way through ethical hacking, cryptography, decoding, logic tasks and much more. while waiting to find out who wins this year, i spoke to an ex—finalist who's now studying cybersecurity at university. and because she is set on a career in the field afterwards, we had to keep her identity under wraps. i think definitely because it is computing there is more pressure to do well because i got to prove myself because i am a girl. it was just that initial leap and then, i was hooked. you see all these women who are very inspirational and you want to live up to them and you don't want to let all the other women down, and you want to help inspire the young people yourself. back to the competition,

and the moment of truth is upon us. the winner is inaudible highgate school! cheering. i really enjoyed the logic and coding ones, but i also really enjoyed cybersecurity, because it required you to think in different ways and use different methods of hacking into some fake websites. it really makes you think of how easy it actually. is to access other people's data and how important i it is to keep your data safe. i had to connect a circuit board. and then once you covered your hand, it would start beeping. and we figured out that those beeping noises when morse code — so, like, dots and dashes — and wrote read those down and found out what those were. in the cryptography sections, so we — if you ever needed to send, like, a coded message to someone, i learnt a lot of different types of codes. after the competition, like, a cyber securityjob is now, | like, an option for me. ah, congratulations to the girls at highgate school! what an inspiring story! now, one of the few films that i got to see the cinema last

year was tenet which, as a massive geek, i absolutely loved. and i know you saw it twice, which i don't think i've ever done! yeah, the second time with subtitles, which i really recommend, because it helps you to understand what on earth is going on. because this is a film where half of the story is going forwards and half the story is going backwards at the same time, in the same scene! so maybe it's no surprise that it won the oscar for best visual effects? yeah, and if you did see it and you wondered how they got cars crashing and building exploding in both directions at same time, well, the answer may surprise you. inversion? aim it and pull the trigger. you're not shooting the bullet, you're catching it. whoa. doing visual effects - on a christopher nolan film is — i imagine is different- from the majority of big budget hollywood films with a lot of visual effects in - because his approach is very much about finding ways - to film practical elements. wherever possible, we wanted

to find ways of filming real - components and mixing it up a little bit so that they felt i very real and grounded i in the real world, but still had that sort of slightly odd, | kind of — it wasn'tjust a case of filming forwards things and reversing them — - there was more than that, | more interesting and more complicated. a really a good example is, i you know, where we have cars pulling away quickly- and they're an inverted car, you would expect the wheels to spin or throw some dust l or gravel out backwards. what we did for those, - we found a way of dragging a car backwards while its - wheels were spinning forwards, so it threw dirt out backwards, but it was going in the wrong i direction. so when then we inverted. the whole thing, so the car pulled away, sucking dust - in to the back into the wheels, so that was a really good - example of the sort of approach

where we find a practical, - real—world event and then just sort of turn it's on its head a little bit so it felt - real but wrong. you want to crash a plane? but not from the air — don't be so dramatic! musical sting. well, how big a plane? that part is a little dramatic. musical sting. the plane crashing into- a building — talking to people since the film came out, everyone assumes that. that is largely cg, or must be — components of that - must be cg. but in reality, that i was actually achieved as a practical event - where we used a full—size, real plane and built - a set and towed the plane into the set and the — - all of the pyro explosions and everything is in the shot for real. i you know, there were visual. effects involved in that we had to clean out the tow ropes and we added jet blasts i to the engines and cgi trees l to be blown around but really,

the vast majority of the chunk of that shot was in camera - and so, it is kind of turning it on its head again a littlel bit in that people assume that it is co but it isn't, l or that some, you know, - major components of it were cg. the end scene in the film - obviously contains a lot of big explosion events, and there's combinations of forwards - and backwards explosions - at the same time and obviously, you can't train an explosionj to be backwards, so we had to add one half of that shot. so whenever there is - a combination of two things, one of them has been added. so we did — we certainly did that a lot for the sequencel where there's a minefield that. people and trucks were running up and down the hilll with mines going off, and we used a combination of practical shot, filmed i elements, but also cg . explosions which had to, incidentally, match exactly the practical ones, -

because they were right next to each other. - another major event in the end battle scene where a building l is simultaneously blown up - by an inverted group of people and a normal group of people, so it is simultaneously- exploding and imploding. so, we built two large — - or they were one—third scale — ten—storey buildings, i two matching buildings, and we filmed each of them i from a matching camera angle and we blew one up at the top and one at the bottom. - and then we could reverse - the film and composite the two together — reverse one - of the films and composite the two together — - so this building had this sort of simultaneous exploding and imploding event. - this reversing in the flow of time — doesn't us being here now mean it never happened? talks backwards. ok, i think spencer's got a bit carried away. as ever, you can find us on the right order on social media — youtube, instagram, facebook and twitter at @bbc click. talks backwards.

i'll tell you what, i'll leave him to it. thanks for watching and we'll see you soon! talks backwards. hello. it seems like everything is running late this spring, and now the april showers have finally arrived. there's nothing like an angry sky to get the weather watchers out. there'll be more like this during wednesday. sunshine, yes, in between the showers, but catch a shower — heavy, hail and thunder and it's going to feel quite chilly as well with the air coming down from the north.

around an area of low pressure which may be some distance away now, but in its way, we have this northerly flow of chilly air, unstable air with the showers developing. we start wednesday with the return of frost possible in any cold rural spots, but particularly into parts of scotland and northern england, as you can see. this zone here is where we're likely to see most of the showers during wednesday. some heavy with hail and thunder. there could be some gusty winds around the showers, although overall, the winds are lighter than they've been. and temperatures, well, they're not going to rise too far. we're just looking really at highs around 8—12 degrees around 8—12 degrees celsius. so, some showers will continue into wednesday evening, perhaps flaring up across parts of northeast england, for example, again wintry on hills. another batch heading south across scotland overnight and into thursday. could well bring some snow to relatively low levels, so that'll be surprising if you see that falling on thursday morning. again, the chance of frost as the day begins. these showers will move on south into northern ireland and northern england. there is an area of cloud and rain flirting with southern parts of england.

still something to play for in how much rain will fall here, so we'll keep you updated. in between the two zones of wet or potential wet weather, there'll be some sunshine. another chilly start on friday morning, another day of sunshine and showers. the heaviest ones look to be focused across eastern parts, temperatures a little bit higher. and then, here comes some more rain. that's from another area of low pressure heading our wayjust in time for next weekend. that means the winds picking up and more rain moving in and as that clears, there'll be showers following. but the air is coming in from the south, so although it'll be windy, although it'll be wet at times, at least the temperatures

will be heading up.

this is bbc news with the latest headlines for viewers in the uk and around the world. mexico city's mayor promises a full investigation into the rail bridge collapse, which has killed at least 24 people. translation: there will be an investigation - by the attorney general�*s office as well as independent experts so that we can find out the whole truth and know what happened. pressure grows for a national lockdown in india as official coronavirus cases pass 20 million. president biden sets ambitious vaccination targets so americans can celebrate independence day. our goal byjuly 4th is to have 70% of adult americans with at least one shot.