this is bbc news. i'm martine croxall. the headlines at eleven: inside the chemical laboratory at porton down — its head dismisses russian suggestions it might have leaked the salisbury nerve agent. we would not be allowed to operate if we had luck of control that could result in anything leaving the four walls of our facility here, so we have complete confidence that there is nothing that could have come from here. police shoot dead a suspected islamist gunman in southern france after he kills three and injures 16. the london offices of the company cambridge analytica are being searched, after allegations of misuse of facebook users‘ data. and on newsnight, we will ask a former us ambassador to nato how successful theresa may has been in persuading europe to crack down on russia following the attack in salisbury. that's newsnight tonight. good evening and

welcome to bbc news. the director of the military research centre at porton down in wiltshire has dismissed russian suggestions that his facility was the source of the poison that left a former russian spy and his daughter in a critical condition. scientists at the chemical defence unit have been analysing samples taken after the attack on sergei and yulia skripal in salisbury. gary aitkenhead told the bbc there was ‘no way‘ the substance could have got out of porton down. our security correspondent gordon corera was given special access to porton down and sent this report. it is one of the most sensitive and a secret sites in the country. porton down, home to the defence

science and technology lab, and now the heart of the salisbury poisoning investigation. inside one of the labs, scientists demonstrated to us one of the many ways used to detect the presence of chemical agents. call came here to porton down in the early hours of monday, march five, and within hours as specialist response team was deployed down the road to salisbury. they collected samples which report back to labs here at the site, and which identified a military grade nerve agent. based on that as well as other information, government has said it is highly likely that russia was responsible for poisoning sergei skripal and his daughter. security at porton down is tight. russian diplomats have raised questions as to whether somehow the no date —— nerve agent from here could have got out. that is something officials say is impossible. we have the highest levels of controls of security around the work that we do here. we would not allowed to operate if we

had lack of control that could result in anything leaving the four walls of our facility here. so we have got complete confidence that there is nothing that could have come from here into the wider world. frustrating when you hear that kind of accusation? it's a coincidence that it's down the road but this has happened, it is frustrated here that because everyone here knows it is not true. they emphasise that their work here is purely defensive. it'll agents are pumped into this chamber to test how well chemical suits given to soldiers stand up. there have been allegations in russia that a new chemical weapons factory is being built, but officials showed us the local planning application saying what is being built here is actually going to be a facility for the analysis of explosives. what about the accusations that there is about the accusations that there is a secret local warfare facility being built here? that isjust nonsense, this is a defensive organisation and we know that the

russians have been suggesting certain buildings are making chemical warfare, and that is just com plete chemical warfare, and that is just complete rubbish. this afternoon the park bench in salisbury where sergei skripal was found were taken away. international inspectors from the opcware international inspectors from the opc w are now taking samples from the scene. they are also working inside porton down itself to independently confirm its analysis, including the conclusions that point to russian involvement. french police have shot dead a gunman who killed three people and injured 16 others in southern france. the attacker, named as 26 year old redouane lakdim, pledged allegiance to the islamic state group. he is thought to have killed and wounded his victims in three separate incidents which began in the city of carcassonne. he is then believed to have driven to a nearby town where he took people hostage in a supermarket. a police officer who swapped himself for one of the hostages is now in a critical condition in hospital, as lucy williamson reports it wasn't a symbol that was

attacked in trebes today. a local supermarket provided the only target necessary — people. special forces surrounded this provincial branch after a gunman burst in, shouting his allegiance to the jihadist group islamic state. translation: people were running everywhere. lots of them were wounded on the ground. our butcher was shot. translation: i took cover, but he saw me, he ran after me. i don't know if he had run out of bullets. i managed to escape through an emergency exit. the gunman was named as 26—year—old moroccan—born redouane lakdim, known to police as a petty drug dealer, but not a violentjihadist. his motive the release of salah abdeslam, a key suspect in the november 2015 paris attacks, currently in jail in france. lakdim began by hijacking a car in carcassonne, killing a passenger and injuring its driver. then he shot and wounded

a policeman — the bullet, passing three centimetres from his victim's heart. before heading to trebes, where he took several people hostage inside the supermarket, shooting two of them dead. with hundreds of police surrounding the building, one senior officer swapped himself for some of the hostages. unknown to the attacker, his mobile phone was connected to his colleagues, listening outside. when lakdim began firing at him, special forces stormed the building and shot the gunmen dead. and shot the gunman dead. the officer is now fighting for his life. france's interior minister, visiting the scene, called him a hero. president macron said he did honour to his office and his country, and that france had once again been the victim of islamist terrorism. translation: i invite all citizens to be aware of the seriousness of the terrorist threat. but also understand the strength and resilience of our people who have been attacked.

tonight, police have raided the flat in carcassonne where redouane lakdim lived. one close associate has been taken into custody. this investigation, raising old unanswered questions about how to spot everyone at risk of radicalisation, and how to tackle a threat that strikes at random in every corner of france. officers working for the information commissioner are searching the london offices of the company cambridge analytica — after a judge granted a warrant. the firm is at the centre of a data privacy row and is accused of using information from 50 million facebook members to try to influence the 2016 us presidential election. cambridge analytica has denied any wrongdoing. earlier our technology correspondent rory cellan—jones spoke to me about the focus of the search warrant. what they wanted to do was go into

cambridge analytica's office and look at the servers, look at the computers, and be assured that the data in question had been deleted. to be clear this was the data collected back in 2014— 2015 by a cambridge academic and handed to cambridge academic and handed to cambridge analytica, data relating to something like 50 million american facebook users. cambridge analytica have issued a statement again about that data? they said all along about "we haven't got that data we deleted it," and the new active —— acting chief executive, because the former chief executive stood down the new acting ceo has said, "we did not any of this data in the work we did in the us election", they also said that when facebook asked them a year ago when

they still had any of this data, they still had any of this data, they searched through all their records and made sure that all the data and all the backups had in deleted, and they say they have told facebook clearly that this has all gone. and cambridge university have now spoken about this academic? there has been a lot of academic —— a lot of interest in what ethical requirements have been made, because if you are an academic doing this sort of research you have to go through quite a process, and the university says that they did go through that process in regards to his academic work. he then later asked whether he could use this data for his work back at the university, and the university said no back in 2015, but does not appear to have asked any further questions. they say they will now undertake a wide ranging review into the whole circumstances of this case and they will ask facebook to co—operate with that review. two lorry drivers have been jailed after causing a crash on the m1 in buckinghamshire that

killed eight people last august. ryszard masierak was jailed for 1h years after being found guilty of causing death by dangerous driving. david wagstaff was sentenced to a0 months in prison after pleading guilty to causing death by careless driving. the teenager who planted a bomb on a london tube train that partially exploded at parsons green has been sentenced to life in prison. ahmed hassan was convicted of attempted murderfor carrying out the attack last september. more than 50 people were injured. he'll serve a minimum of 3a years. a police inspector has been found guilty of murdering his wife and dumping her body in a lake. darren mckie killed his wife leanne after she discovered he'd been taking out loans in both their names. jurors at chester crown court heard how the couple, who both worked for greater manchester police, owed more than £100,000. owen smith has been sacked from jeremy corbyn's cabinet after calling for a second referendum on brexit. the shadow northern ireland secretary broke ranks with labour party policy by also making the case for the uk to stay in the single

market after brexit. he's been replaced by tony lloyd. owen smith reacted to the news on twitter. he said: the shadow home secretary diane abbott said that mr smith should not have spoken out in the way he did.|j would smith was a valued colleague, he wanted to make a contribution to the debate, and he will be able to do so, what he can't do is sit on our front bench and advance a position which is simply not labour party policy. but no one is saying he can't have his own opinion, but we are clear, we want a meaningful

vote on defining the deal —— the final bill in parliament because after a ll final bill in parliament because after all we are a parliamentary democracy. we are not calling for a second referendum. european union leaders in brussels today said they were preparing coordinated measures against russia following the salisbury attack. separately, they approved guidelines for the negotiation of future relations with the uk — in what's being seen as a key step in the brexit process. plans for a transition period after march next year were also formally signed off, as our political editor laura kuenssberg explains from brussels. they don't always look so pleased to see each other. the eu's chief negotiator grasping the prime minister's hand. today, the day when formally, finally, the stage right after brexit, the transition, was agreed. i welcome the fact that the eu council this morning has agreed the details of the implementation period. this gives certainty to people and businesses.

it gives them the clarity to plan for the future. i believe we are approaching this with a spirit of cooperation, a spirit of opportunity for the future as well. not much will change for nearly two years after we leave, but how closely will the uk hug the continent after? that is the next fight on the table, the next details to work out. time is of the essence, the eu's most powerful voice said. translation: if the uk wants to leave the customs union and the single market, that means a free trade agreement, germany's angela merkel said. agreeing a buffer zone between leaving the eu and cutting off all ties was never in doubt today. but theresa may's argument also swayed eu leaders to turn up the pressure on russia. the union even pulling back its own ambassador here to brussels. perhaps, after months of difficulties, britain's stock here is on the up.

it's notjust the eu ambassador leaving moscow. other european countries say they will send russian diplomats back there, in coordinated moves next week. but leaders here have been willing to walk the walk alongside britain. matching theresa may's stance. in contrast to an awkward pause yesterday. the european union agrees with the uk government assessment that it is highly likely that the russian federation is responsible for this attack and that there is no other plausible explanation. despite the tough brexit negotiations, the european union has demonstrated unanimous and unequivocal unity with the uk in the face of this attack. we decided to call back our european ambassador in moscow. this is an extraordinary measure, we never took it before.

this time, although the uk is leaving the eu, the continent still stands together. the next 12 months could fray those alliances. then she will make this departure for the final time. that's a summary of the news, newsday is coming up at midnight — now on bbc news it's time for newsnight. and you thought the age of chivalry was dead. and looking at the salisbury poisoning. translation: reconsider this is an attack to european sovereignty.