daughter in the city last sunday. they're from the royal marines, the raf, and some are specialists in chemical warfare. they'll help remove vehicles and objects from the scene which may have been contaminated. sergei and yulia skripal are still critically ill in hospital, while the policeman who tried to help them remains in a serious condition. richard galpin has the latest. six days after the attack here in salisbury and now the police and forensics experts are to be joined by around 200 soldiers specially trained in chemical warfare. theirjob, to help secure key locations,

recover evidence and remove contaminated vehicles. also today the home secretary visited the area and praised the emergency services for how they responded to such a dangerous incident. they reacted with the professionalism and compassion you would hope our emergency services do and i am awe of their sympathetic approach and professionalism. meanwhile the double agent sergei skripal and daughter yulia, who travelled from russia to spend time with her father, remain in a critical condition in salisbury hospital. but they are said to be stable. sergei skripal‘s house is another major focus of the investigation, with evidence being collected here and the building possibly being decontaminated. at the research laboratories in porton down, scientists may have already identified the nerve agent used the attack, which almost certainly would have been made in a state—run

establishment. and that could well reveal who targeted sergei skripal and his daughter. but why were they targeted now? sergei skripal is one of a large community of russians living in this country. some of them left russia in fear of their lives. here in surrey, i have been speaking to one of those exiles, who met sergei skripaljust a couple of months ago. he told me that in the chance meeting, sergei skripal had talked about how he regularly met up with russian diplomats here and about the work he was involved in. he said, i'm doing business, a different kind. but i closed down my business in spain. i am working mainly in cyber security. did he say what he was doing in cyber security? no, and i was not asking, because a sensitive question. but i understand he was working for some russian groups.

but working with people in the embassy on this, or something separate? no, i had a feeling that meeting with friends was one and cyber security, his business, was another. so could that work in cyber security possibly be the motive for the attack? richard galpin, bbc news. our home affairs correspondent leila nathoo is in salisbury. what's the latest? police here are clearly dealing with a deadly substance, so that is why the military are sending reinforcements, 180 military personnel coming here to insist the investigation. they are taxed with removing evidence, objects and vehicles from the scene in salisbury town centre but it is understood that they could also be involved in

recovering potentially contaminated ambulances. the police are stressing that there is no need for people to be alarmed by the military‘s coming here and there is no wider risk to the public, no increased risk to the public. it is just to help with the investigation. this morning the home secretary, amber rudd, visited the scene here, the bench still under the police tent behind me. she came and talked to people affected, local businesses, first responders and she visited detectives nick bailey, the police officer in hospital after being exposed to that chemical. the police investigation is focused on and above locations in salisbury city centre but there has also been a pick—up in activity at sergei skripal‘s home, about ten minutes away from here, yesterday. we think the police are in for a lengthy operation there as they tried to recover evidence to try to figure out how and when sergei skripal and his daughter yulia were exposed to that nerve agent.

thank you very much, leila nathoo. 0ur defence correspondent jonathan beale is here. how unusual is it to see military personnel on the streets of britain and who exactly are they? the fact is most military personnel go through some kind of chemical weapons training and where gas masks and are aware of the threat. there are specialist out there who would not be a normally on the streets and thatis not be a normally on the streets and that is why ministers are saying, don't be alarmed when you see these people turning up. they have got skills that will be vital to helping the police in chemical warfare. they have specialist vehicles which can carry out what is called sensitive site exploitation. they can trace where the chemicals may have gone, sent back samples and analyse them. they have vehicles which are essentially mobile laboratories which can carry a decontamination and they will also remove some of the vehicles that may have been contaminated, like the ambulances that ferried people to hospital. people might think this is very

worrying. i think the message from ministers is that you should be reassured, the people have the expertise and skills and the threat hasn't changed. they will be there to secure the site is already secured and help police find those objects, fibre traces of the chemical, and to make sure this is a thorough investigation. jonathan, thank you. jonathan beale there, our defence correspondent. president trump says he will meet north korean leader kim jong—un for talks by the end of may. the north koreans are reported to be committed to denuclearisation and ending missile tests. the apparent breakthrough comes after months of growing tension, in which the two leaders have traded insults — kimjong—un called mr trump "mentally deranged". the american president called him a "maniac" and "little rocket man". laura bicker has this report from south korea. the missiles and displays of military might from north korea have almost seemed defiant in the face strict sanctions and international condemnation. but now it seems kim jong—un wants to talk. he made his new position clear over

food with south korean officials in pyongyang. it was the first time ministers from seoul have met the young leader. they say he is prepared to discuss getting rid of his nuclear weapons and they've now delivered a message from kim jong—un that caught many in the white house by surprise. he expressed his eagerness to meet president trump as soon as possible. the idea of a face—to—face meeting between president trump and kim jong—un by may seems remarkable, given the months of threats and insults between them. they will be met with fire and fury. rocket man is on a suicide mission for himself. but the tone has changed. on twitter, donald trump said that great progress was being made but that sanctions will remain until an agreement is reached. however, that meeting is being planned. the us secretary of state

seemed blindsided. just hours before coming he had this to say. in terms of the direct talks with the united states and us negotiations, we are a long way from negotiation. given the unpredictable nature of donald trump and kimjong—un, could this meeting even go ahead? there's all kinds of obstacles on the road to the summit between now and then. it may be simply that president trump changes his mind. this wouldn't be the first time, would it? it may be the senior officials get to him and say, "mr president, not in may, let's prepare properly. " you can'tjust wing it policy on north korea. getting kim jong—un to give up his prized nuclear weapons is a tough ask. analysts in seoul are cautious and believe this is just the starting line. the road ahead is very long and complicated, very complex and it is not guaranteed that the north will ever give up its nuclear weapons easily, if at all.

the us and south korea are due to hold joint military exercises at the end of this month. last september, the us flew bombers over the peninsula as a show of strength. this usually infuriates north korea and prompts missile test. this time they say they will understand. it may be a move away from fire and fury, potentially towards friendship. but that would depend whether the message from pyongyang is one of genuine progress and not propaganda. laura bicker, bbc news, sold. in a moment we'll speak to barbara plett usher in washington but first to laura bicker in the south korean capital seoul. so, laura, this looks like a really significant breakthrough — if it happens. the president here in south korea has described it as miraculous. it did seem utterly unthinkable just a

few months ago but this is something that the south korean government have been working towards, deftly, diplomatically trying to work with kim jong—un diplomatically trying to work with kimjong—un and diplomatically trying to work with kim jong—un and trying to work with the united states. but it is a huge political gamble for both president trump and president mum. getting kim jong—un to give up his weapons is a very difficult thing to do, even if right now he says he is prepared to discuss denuclearisation. there has to bea discuss denuclearisation. there has to be a payoff. what does kim jong—un want in return? so that is the gamble. what will be the carrot in return for the stick which has been these international sanctions? the other thing here is cautious optimism. that is the phrase that many are using. they're optimistic in south korea because this is a real opportunity, for the first time. they are now even mentioning in whispers something that they have been trying to get for at least

seven decades, and that is the possibility of a peace treaty. laura, thank you very much indeed, and to barbara platt chanel. what is going on in the white house, after such a hard line on north korea from donald trump, why has he agreed to meet kim jong—un? donald trump, why has he agreed to meet kim jong-un? seems like a big difference but remember that he has actually swung pretty wildly between threatening and insulting kim jong—un and then musing about the possibility of sitting down with him. asa possibility of sitting down with him. as a candidate he said, "maybe i will meet kimjong—un him. as a candidate he said, "maybe i will meet kim jong—un and sit down and have a hamburger with him." so that is his style, to move from one end of the other and see where it lands. i think it would be quite appealing for him to be the first sitting president to meet the north korean leader and i think you'll make the most of it. but he has said sanctions will remain regardless, whether there are talks, and the policy is to isolate north korea politically and diplomatically while presenting a clear military option.

there has been a clear emphasis between the white house on the state department on that. the white house has been much more willing to consider a military option, whereas the state department has said, we need to at least get in the state room. secretaries tillerson said we should at least have talks about talks so doesn't seem the underlying policy has changed but what has changed is kimjong—un has said he is willing. about giving up his nuclear weapons, a big surprise especially because he's so invested in it. there is scepticism about it here but it seems they are willing to ta ke here but it seems they are willing to take the opportunity. barbara thank you, and thanks to laura bicker in seoul. the government says it will seek a british exemption from new tariffs on steel and aluminium exports to the united states. president trump says the tariffs are to defend america from what he's called "an assault on our country". but employers and unions in the uk steel industry say the measures could have "devastating" consequences. here's our business reporter rob young. the uk has managed to forge a global reputation for making high—quality steel products.

a company in sheffield makes parts of submarines for the american navy. but the industry is worried president trump's steel import tax will hit producers here hard. what we will now see is uk companies really suffering from president trump's slapping in effect a 25% tax on all their exports from the uk to the us. and that will hit us hard. each year, the uk sells £360 million worth of steel to the united states. that's 7% of all the steel britain exports. it's bought by america's defence, aerospace and energy industries. president trump's plan to impose a 25% import tax on steel will make the tissue products more expensive and less competitive in america. —— british products. we import a lot of speciality steels

and europe, and recount in continued to import that speciality steel from europe because it's not available in the us. so for that steel we purchase from europe, it's going to cost us 25% more. these new tariffs have led to political sparks flying in the us and globally. britain disagrees with the tariffs. the european union and others are warning they will retaliate. president trump has said he will be flexible towards america's real friends, the british government intends to put view across next week. we'll be looking to see how we can maximise the uk's case for exemption under these particular circumstances, but we will want over the next few days to look at them in great detail. there a wider fear that steel bound for america will now find its way into other countries. a flood of steel could push global prices down. that's potentially good for consumers but a double whammy for the industry. many of the same countries who are in the top ten of us exporters are the same who go to europe, for example brazil and turkey are both large exporters to the us, they will turn their boat around

and head straight for the eu. trade deflection could have much, much larger effect on the industries in the actual loss of exports themselves. president trump's intention is to protect america's steel industry but there is a very real fear he will end up hitting steelmakers elsewhere. a long—awaited humanitarian aid convoy has crossed into the rebel—held enclave of eastern ghouta in syria where an estimated 400,000 civilians are trapped by the fighting. but the un is warning that it may have to pull back because of renewed violence. martin patience is following developments from beirut in neighbouring lebanon. what is the latest you are hearing on the progress of the convoy? this is the third time the international community has tried to get humanitarian assistance to the

people of eastern ghouta and nine out of the 13 trucks we here have been unloaded but it is not clear whether the four remaining trucks, food supplies from them will be off—loaded and the reason is continued shelling in the area. it is worth pointing out it was humanitarian assistance that should have been delivered on monday and the reason it was not delivered then was because of shelling. yesterday the convoy was cancelled because of security concerns. it underscores how difficult it is for the international community to get assistance to the people of eastern ghouta. 400,000 people estimated to live there and if they manage to deliver the aid, international organisations say it is not enough. whilst the international community is focusing on getting aid to eastern ghouta, the syrian government backs by its russian ally

appeared determined to take the last major rebel stronghold close to the capital. the latest figures, more than 900 civilians have been killed in fighting since this major government offensive began. martin, thank you. our top story this lunchtime... almost 200 military personnel are deployed to salisbury — after the nerve agent attack on a former russian spy and his daughter. and still to come... rethinking stonehenge — historians say the neolithic structure may have been built as part of a community celebration. coming up in the sport, a little bit rusty but no problems for serena williams she wins on the wta tour for the first time in over a year and six months after giving birth to her first and six months after giving birth to herfirst child. the arduous task of building stonehenge may have been part

of a ceremonial celebration — according to historians studying the ancient site. the stone circle in wiltshire was built over 4,000 years ago using stones from south wales — a fact that has long baffled experts, but english heritage now says selecting, moving and setting up the the stones on salisbury plain may have been a way of bringing people from all over the country together. duncan kennedy is at stonehenge. duncan. you might think that after 4500 yea rs you might think that after 4500 years we would know everything about this monument but that is not the case, particularly with regard to the building of it and today's report says it may have been the construction of the monument, it could have been more important than the end result. today dozens of volu nteers the end result. today dozens of volunteers turned up to help prove the point. one, two, three, pull.

heaving for history. volunteers at stonehenge today trying to repeat what neolithic people did around four and a half thousand years ago. do you currently feel like neolithic woman doing this? that is an interesting concept, yes. yes, i do. the aim of the experiment was to see how this ancient monument was built. historians now say it was the construction process itself as much as the end result that mattered. we know it was a prehistoric temple aligned with the movements of the sun. it was used as such. the building process and alterations, changes coming together as a community might have been more important factor. english heritage say the photos of people in indonesia, taken 100 years ago, helped to prove their point.

the images show how moving great rocks has long been accompanied by dancing and dressing up in costumes. they say it was probably the same spirit that helped to build stonehenge, with people drawn from across britain to come and feast and make building a festival. we need to come back literally four inches. in old money! in other words, a celebration of construction. recreated today. words, a celebration of construction. recreated todaym words, a celebration of construction. recreated today. it is actually 0k, not too bad. how about you? it is fine. not too bad. shall be tried again? brings the ropes closer together. the stone is so heavy, we have asked for more volunteers. it weighs four tonnes. this is hard work. this is the first time an official rock pull like this has taken place at stonehenge.

time an official rock pull like this has taken place at stonehengem time an official rock pull like this has taken place at stonehenge. it is partial success, not exactly vertical, but it has been raised. it shows the effort required just for a four tonne stone. it does not always go to plan. yet even with the odds tumble the experiment shows what can be achieved when strangers come together for a be achieved when strangers come togetherfor a common be achieved when strangers come together for a common good. be achieved when strangers come togetherfor a common good. and in doing so, helping to form our preconceptions of prehistory. if you are looking to take part yourself, you are welcome to come along this weekend because stonehenge is organising two days of experiments to show people they can join in what the people of the neolithic era did 4500 yea rs the people of the neolithic era did 4500 years ago. duncan, thank you. have a rest! how do we rid our oceans of plastic? it's a problem that's had a huge amount of

attention in recent months. now scientists are asking members of the public to help with efforts to clean up britain's coastline with the help of new technology — but from the comfort of their own homes. danjohnson has been to the south coast to find out more. 0ur beaches are the front line in the war against plastic. new technology is being used to get a better idea of the scale of the problem. an eye in the sky capturing the waste on our shores. we use a drone to survey very quickly and efficiently lots of inaccessible beaches, as well as public beaches, and we take thousands of photographs. we upload those photographs onto an online platform and then anybody in the country, whether they are scientists, not scientists, children, adults, can log in and tag where they see plastics in the photographs. that means the clean—up teams can focus efforts on the worst—hit places. but picking up the plastic

still needs people power. we need to get involved for two reasons. one is about awareness, awareness of the problem plastics are causing on our planet, particularly on our beaches and seas, so that when we make choices, buying coffee, or are in the supermarket, we can make better and more informed decisions. but also, actually making us all realise that science is something we can all be part of. it is notjust for people who are in labs or went to university. we can all be involved in helping scientists understand our world and making it better. this was collected in just a couple of hours this morning and gives an idea of the sort of stuff that is around on our beaches. the visual evidence of this problem. but, actually, the majority of the plastic that is a real issue is right out there. more than 8 million tonnes of plastic goes into the ocean every year. much of it so small it is barely visible. it is estimated less than 1% is collected. what we see on the beaches is just a fraction unfortunately of what is in the oceans.

the beach is a really good place to clean up and to really try to address that but ultimately we need to stop the plastic going into the oceans in the first place. the sands may be shifting, but we have still barely started getting to grips with the true nature of the plastic problem. dan johnson, bbc news, near brighton. last week's cold weather and heavy snow across the country caused huge disruption to the health service, with many operations cancelled. but lindsay chisholm — a surgeon at a paisley hospital — was so determined not to let down her patients, she walked eight miles through heavy snow and blizzard conditions so she could to perform a crucial operation. lorna gordon has the story. the top story, scotland continues to battle the beast from the east. they we re battle the beast from the east. they were conditions more akin to mountains on city streets. the

blizzards, sub zero temperatures and snow that kept falling meant no buses, trains and few people venturing out. it was not enough to put off one very determined surgeon. i got put off one very determined surgeon. igot up put off one very determined surgeon. i got up early on thursday and saw there was a lot of snow but it did not look impossible and i thought i would head into work. when i arrived, two colleagues would the first eyesore. took one look, started laughing, and they said how did you get here? i said i work. lindsey was well prepared. she had winter clothing, snow shoes and walking poles to help through the deepest drifts. completing the eight mile trek to the hospital in just under three hours. her patient feared his surgery for cancer would be postponed. it felt like christmas day. she told me she walked in from

home. i could not believe she had walked almost eight miles to do surgery on me. walked almost eight miles to do surgery on me. if there is a real—life superwoman, she is it, for me anyway. the surgeon insists she was just me anyway. the surgeon insists she wasjust doing herjob.|j me anyway. the surgeon insists she wasjust doing herjob. i did not think it was a big deal, i put my winter kit on and walked to work. it is as if the world has gone mad! lindsey has been left bemused by the attention, insisting many others went the extra mile to keep the nhs going through the storm. the winter paralympics are officially under way after an opening ceremony in the korean resort of pyeongchang. paralympics gb are sending their biggest team since 2006 and hoping to win up to a dozen medals. kate grey is in pyeongchang. it was just under two weeks ago the

0lympics drew to a close in pyeongchang and now it is the turn of the paralympics. the crowd were treated to a spectacular opening ceremony and despite weather issues and problems with rehearsals, it went off without a hitch. the biggest winter paralympics to date. drummers and dancers, the traditional charms of korea opening the show. nothing could be done about the fog covered fireworks. heavy snow prevented a full rehearsal so a slight fly kick up could be forgiven. onto the parade. here they come, great britain. 0wen pick leading the way. a great honour for the soldier turned snowboarder. the british team enjoying the party atmosphere. the international

paralympic committee atmosphere. the international pa ralympic committee wanted atmosphere. the international paralympic committee wanted north and south korea to march under a unified flag. the team preferring to walk out separately. the host nation completing the procession. the cold meant no hanging around with teams sneaking in and out of the stadium. the crowd were treated to an eclectic mix. a snowboarding bare. weird and wonderful contraptions on wheels. and the flaw putting on a dazzling show with the help of performers. formalities were also there. the flame brought into the stadium in the united hands of north and south korean athlete before lighting the cauldron in and south korean athlete before l|ght|re fog uldron in and south korean athlete before l|ght|re fog uldron ii for fféifl'flfifiil fifefieefee flfiile tee' fféifl'f'eeil fifefieefee fieele tee | begins ‘ with british if tee weather

behaves, alpine skiing begins with the downhill and there will be medal hopes resting on the shoulders of athletes. they will be hoping to get back on the podium. elsewhere, scott mina will represent great britain for the first time in nordic skiing for the first time in nordic skiing for the first time in 20 years. competing in six out of the eight days. finally the curling team will hope to begin their campaign with a win. a busy day to start here. thank you. and now the weather.