welcome to bbc news, broadcasting to viewers in north america and around the globe. my name is nkem ifejika. our top stories: professor stephen hawking, world famous physicist and author, dies at the age of 76. russia defies a deadline to explain the nerve agent attack in britain that left a former spy and his daughter fighting for their lives. as international pressure mounts, moscow warns any punitive measures will be met with a response. hours after the us secretary of state's shock sacking, a breathless rex tillerson bows out of public life. what is most important is to ensure an orderly and smooth transition during a time that the country continues to face significant policy and national security challenges. and the black directors behind blockbuster movies, diversity finally hits hollywood. hello and welcome to the programme.

we start with breaking news, professor stephen hawking has died at the age of 76. he was known for his ground—breaking work with black holes and relativity, and was the author of several popular science books including, a brief history of time. as a young man, he was stricken with a form of motor neurone disease. nick higham looks back on his remarkable life. he was instantly recognisable and utterly remarkable. a visionary scientist, helpless in his high—tech wheelchair, who nonetheless transformed our view of the universe. while a student, he developed the first signs of motor neurone disease. gradually his body shut

down until he could communicate only using a computerised voice synthesiser, controlled to start with by hand. it didn't hold him back. i was never actually told that i had only two years to live, but i could see the doctors didn't think my prospects were good. his fame sprang from his book, a brief history of time, it sold 10 million copies. but although many bought it, rather fewer actually read it. his theories about time, space and black holes were stupendously difficult for nonspecialists to grasp, but he turned out to have a genius for communication. he gave lectures and interviews and became an unlikely celebrity. he even appeared in the simpsons. i don't lie to your tone. if you're looking for trouble, you've found it. yeah, just try me... the public loves to have celebrities who aren't the run of the mill celebrities are so when you have

someone celebrities are so when you have someone who achieves a significant intellectual accomplishment and becomes famous, people like me go, great, i wish there were more of them. on an episode of star trek key play poker with isaac newton, his predecessor as lucretia and of mathematics at cambridge. not be apple story again. he became a byword for cleverness, an unlikely international pinup. he fills that sort of place we need for a symbol of brainpower. if you go intoa for a symbol of brainpower. if you go into a student's room these days, instead of seeing john lennon, jimi hendrix or che guevara, unless in a retro sense, you see oscar wilde, ironstein, stephen hawking, people like to identify themselves being on side of the mind think of themselves asa side of the mind think of themselves as a pure symbol of that, a pure brain. his first life was conjugated, his wife, jane, he had three children

with and then in 1990 he left for his nurse, elaine, they eventually married only for claims to urge he had been physically abused. police investigated but the case was dropped for lack of evidence. the couple later divorced. he never lost his sense of humour. though by the end, he could only speak by twitching his cheek to move an infrared beam. i don't have much positive to say about motor neurone disease, but it taught me not to pity myself and to get on with what i still could do. i am happier now than before i developed the condition. if general relativity is correct then the universe is expanding, yes? yes. so if you reverse time then the universe is getting smaller? all right. in 2014 his life was

dramatised in the theory of everything with eddie redmayne playing hawking. what happened with the beginning of time itself? stephen comedy you are. at cambridge they unveiled a statue for him, a rare honourfor someone still living. but few did more to inform our understanding of the universe and to overcome personal challenges. a statement has been released by professor stephen hawking's family, it says, "we are deeply saddened that our beloved father passed away today. was a great scientist and an extraordinary man whose work and legacy will live on for many years". it goes on to say his grips persistence and brilliance with humour inspired people around the world. he once said," it would not be much of a universe if it wasn't home to the people you love". " we will miss him for ever". professor stephen hawking, who's died at the age of 76. russia has ignored a midnight

deadline set by the british government to explain how a nerve agent, thought to be russian—made, was used to poison a former spy and his daughter. sergei and yulia skripal remain in a critical condition in hospital. moscow continues to deny any involvement in the attack. our correspondent, sarah rainsford, reports from moscow. accused of a crime many miles from here, under pressure to explain a chemical attack that shocked britain. but today, the kremlin has remained silent. the foreign minister, though, was in full defensive flow. sergey lavrov rejected britain's 24—hour ultimatum to respond to the claim that moscow used a nerve agent. "russia should get 10 days," he said, accusing britain of flouting the chemical weapons convention. and when i asked about the actual charge, the minister called that nonsense. translation: russia is not guilty.

russia is ready to co—operate in accordance with the convention on the prohibition of chemical weapons if the uk finally decides to fulfil its obligations under international law within that document. russia's also demanding a sample of the substance used in the attack to conduct its own tests. it's been identified as novichok, which the bbc believes was once produced here in a secret soviet programme. reports in moscow say any stockpiles were destroyed long ago. so when the british ambassador was called to the foreign ministry, moscow says he came to hear its protest at a sordid attempt to discredit this country. i reiterated the points made by prime minister may that we expect by the end of today an account from the russian state as to how this material came to be used in salisbury. russia has always insisted it had nothing to do with the poisoning

in salisbury, and that position clearly hasn't changed even with the threat of sanctions. after all, this is a country that's been living under international sanctions for some time, linked to its actions in ukraine. and those measures haven't weakened president putin politically at all. if anything, they've made him stronger. moscow, then, is in no mood for ultimatums, and it will continue to insist on its innocence. sarah rainsford, bbc news, moscow. in a separate but interesting development, a russian exile who'd been granted political asylum in britain, nikolai glushkov, has been found dead at his home in south—west london. police say they are treating the death as unexplained. scotland yard has given further details about the movements of sergei skripal and his daughter yulia in the hours before they became critically ill. daniel sandford has the latest. today, with nerve agent contamination still a huge concern,

police were working at the pound where sergei skripal‘s car was found after being towed away from salisbury town centre. britain's most senior counter—terrorism detective warning today that the complex operation in the city will last many weeks. we are sifting and assessing all evidence available and we are exploring all investigative avenues, this includes extensive cctv footage from across the city and over 380 exhibits so far. detectives now believe yulia skripal arrived at heathrow airport from russia on the afternoon of saturday, the third of march. the next day, the day of the attack, she and herfather, sergei, drove into salisbury in this red bmw. police are asking anyone who saw the car between 1pm and 1:45pm that sunday to come forward. at 1:40pm that afternoon, they parked on the upper deck of the sainsbury‘s car park from where they walked past a small park to the mill pub. after a drink, they headed to the zizzi restaurant,

where they were between 2:20pm and 3:35pm. they then headed back to the park where, at 4:15pm, they were found desperately ill on a bench. today, police said detective sergeant nick bailey, who also became seriously ill after getting contaminated, was making good progress. the two people targeted in the attack, yulia and sergei skripal, are still in intensive care here in salisbury hospital, where staff are having to use special precautions because of the military grade nerve agent. they're both in a critical condition, but they are both still stable, which means they're not getting significantly worse. i understand that she is doing slightly better than he is. we still don't know if detectives have a specific suspect in this unique and challenging investigation, they said they wouldn't be making that public at this stage. daniel sandford, bbc news, salisbury. let's take a look at some of the other stories

making the news. the syrian government has allowed the first medical evacuations from eastern ghouta. the besieged opposition stronghold has been the focus of a major government offensive for the last three weeks. the un says more than a thousand people are in desperate need of medical attention. prosecutors in florida say they will seek the death penalty for the teenager charged with shooting dead 17 people at a high school last month. they say nikolas cruz acted in a cold, calculated and premeditated manner and that the shooting was especially heinous. the former south korean president, lee myung—bak, has reported to prosecutors for questioning in a corruption probe. the 76—year—old has been facing allegations of corruption involving his family during his time in office. speaking to reporters outside he said he was "very sorry for causing concern to the people." venezuela's secret police have detained a former interior minister, miguel rodriguez, who has become an outspoken critic of president nicolas maduro. in a statement, the government accused mr rodriguez of planning armed attacks and conspiring against the country's constitution. the us secretary of state rex

tillerson has made his first statement since being sacked by president trump, conspicuously failing to thank his former boss or praise his policies. the president told reporters that he and america's top diplomat had a different mindset on key issues, including the iran nuclear deal. the director of the cia, mike pompeo, has been named as mr tillerson‘s replacement. our north america editor, jon sopel, reports. after a long trip to africa glad—handing and promoting the us, rex tillerson flew back to washington overnight. but unbeknown to him, the president had signed his death warrant, and it would be death by tweet. but tillerson isn't on twitter, so excruciatingly it fell to his chief of staff to inform him of his demise.

there was no contact from the white house, only this afterwards from the president. i think rex will be much happier now, but i really appreciate his service. happier? he didn't seem it. in his farewell statement, he never mentioned donald trump by name, didn't thank him or wish him luck. instead, there were these pointed remarks on russia. much work remains to respond to the troubling behaviour and actions on the part of the russian government. russia must assess carefully as to how its actions are in the best interests of the russian people, and of the world more broadly. i, rex wayne tillerson, do solemnly swear... it was all so different when he was sworn in, then seen as one of the grown—ups of the administration. but his fate was probably sealed last october when it was reported he called donald trump a moron, an accusation he didn't exactly deny. i'm not going to deal with petty stuff like that. i mean, this is what i don't

understand about washington. again, you know, i'm not from this place, but the places i come from, we don't deal with that kind of petty nonsense. then there was the public undermining of the secretary of state by the president, sending family to do work that would normally be done by america's chief diplomat, and public shaming on twitter, like this. there's not much love lost between donald trump and rex tillerson, they disagreed on policy and didn't much like each other personally. mike pompeo will be much more to donald trump's taste and it's vital they do get on given the importance of subjects like north korea. but will he be the man who says to the president, "i think you're wrong," as rex tillerson did? tillerson was isolated trapessing around the world with little support in washington. in his previous life, the former ceo of exxon was a corporate titan, but he's now political roadkill. surely the place with the lowest

life expectancy anywhere in the world, being a member of the trump administration. another senior figure who didn't smell the coffee. jon sopel, bbc news, washington. stay with us on bbc news, still to come: what can i do for you, mrs whatsit? a bittersweet moment for the black director of hollywood blockbuster a wrinkle in time. the numbers of dead and wounded defied belief. this, the worst terrorist atrocity on european soil in modern times. in less than 24 hours then, the soviet union lost an elderly sick leader and replaced him with a dynamic figure 20 years hisjunior.

we heard these gunshots in the gym. then he came out through a fire exit and started firing at our huts. god, we were all petrified. james earl ray, aged 41, sentenced to 99 years and due for parole when he's 90, travelled from memphis jail to nashville state prison in an 8—car convoy. paul, what's it feel like to be married at last? it feels fine, thank you. what are you going to do now? is it going to change your life much, do you think? i don't know, really. i've never been married before. this is bbc news. the latest headlines: professor stephen hawking — world famous physicist and author of a brief history of time — has died at the age of 76. in a statement, professor hawking's children said they were deeply saddened.

they described him as an extraordinary man whose work and legacy would live on for many years. moscow has failed to respond to british demands to explain how a nerve agent made in russia was used to attack a former spy and his daughter. let's stay with that story. i don't think there's much the uk can do to make russia stop any such actions. russia has been under sanctions for quite a while and it's only made putin more popular and stronger at home. it continues a narrative of russia under assault from the west. so there really isn't much the uk can do to stop it.

if the uk can't do anything on its own, how about collectively with nato or with eu allies, with the united states involved? surely that collective power will have some clout? russia is already under sanctions from the west. the uk and other western european countries could obviously pull out of the world cup. however, i think that ultimately nothing will change russia's perspective, especially this being an election year. this is a man who, as far as we understand, has not necessarily been involved in the russian spy scene for a while. what is the rationale, if indeed russia is involved, what is the rationale for russia doing this now? i think the rationale is twofold. first of all, it's an election year, it makes putin look stronger. it reiterates russia under assault from the west. but it also sends a clear signal, if, again, russia is involved, it sends a clear signal that anyone who betrays russia or defects to the west is going to get hurt by russia eventually. it's only a matter of time. there's a picture on the front page

of the times here in the uk, the gulf state of qatar will be introducing a sugar tax later this year — a move partly prompted by health surveys showing that 70% of qataris are overweight or obese — almost double the global average. the government is taking action to try to get people to lose weight and it's also set to start screening adults for diabetes. our global health correspondent tulip mazumdar has been given rare access to the qatari health system. it's time for the weekend shop and families are stocking up. the jamals' are trying to make healthier choices. it's because, atjust 16 years old, jabor‘s poor diet, he tells me, led to him developing type 2 diabetes. translation: when i was a kid, i really loved sweets.

we would just eat, go to bed, wake up the next day and eat more. qatar has become one of the richest countries on earth thanks to the discovery of oil and gas here. with all that wealth though came a massive influx of international workers and western tastes. in a very short period of time, qataris have totally changed how they live, where they live and what they eat. they've gone from active, outdoor desert living to much more indoor sedentary lifestyles and many are now paying the price for adopting some of the worst of western excesses. qatar is now building more outdoor areas, like this one, it's introducing a sugar tax this year and improving food labelling. we declare it's an epidemic. everyone knows and there is a high political commitment to face this. we try to find the best approach to tackle this. one of those approaches is funding new research, salem is part of a study targeting younger people trying to reverse their type 2 diabetes. translation: i used to eat very chaotically.

for breakfast i'd eat sandwiches, for lunch i'd have a lot of meat and i'd have a heavy dinner. i started feeling pain in myjoints and my feet. left untreated, the disease can cause blindness and even foot amputations. almost one in five people suffer with the condition here, but through this strict diet and exercise programme patients are going into remission. we need to see the long—term outcomes, but it is possible medically to take younger people, get them fit, improve their life without any medication, without any surgery. all these mixture of medals... aldana is part of the women's national handball team and wants to help fight the obesity crisis. she says people need better education on living well. by increasing the awareness and doing programmes forfamilies. they're not aware how much is dangerous for the children. they've started to get this information about healthy lifestyle. unlike many other countries,

qatar certainly has the resources to deal with its obesity epidemic. the bigger challenge is ensuring its people have the will. disney's new film — a wrinkle in time — had its european premiere in london a few hours ago. the film which stars oprah winfrey and reese witherspoon is already doing well at the box office in america. what makes this film different, it's the first time a black woman has directed such a big budget film — costing more than $100 million. but ava duvernay says for her, it's a bittersweet moment. your father has accomplished something extraordinary. based on the 1962 fantasy novel, a wrinkle in time tells the story of a young teenage girl whose scientist father goes missing and it's down to her to find him and save the universe. and the only one who can stop it...

is you. wrinkle currently holds the number two spot at the us box office. in at number one is the marvel epic black panther which has also just surpassed the $1 billion mark worldwide. to the rest of the world. plus, it's the first time in history that two black directors with budgets over $100 million have ever taken the top two spots at the box office. an achievement the wrinkle director ava duvernay, has described as bitter—sweet. there are amazing women throughout history of cinema who were black women, women of colour, who should have had these opportunities but hollywood and the industry didn't give them the opportunities. so because hollywood has decided to give me the opportunities, it doesn't have anything to do with me, itjust has to do with the time. so it's bitter—sweet when we hear of some of these firsts happening in 2018.

do you think hollywood's changed towards people of colour being forefront and centre of film? changing, not changed. changed means it's done and it's happened. that's certainly not the case. but changing, i hope so. that hope is turning into a reality. since the start of her career, ava has insisted on a diverse cast and crew. something other production houses and actors are now actively including in their contracts in hollywood. here, we're trying to make something that loves a wider audience and we say, we love you back. if you're a girl, if you're a person of colour, if you're a caucasian boy, if you're a south—east asian woman, if you're a filipino boy, we have everybody in this film ‘cause we want the film to love everyone so they can see a bit of themselves in it. chi chi izundu, bbc news. professor stephen hawking has died

at the age of 76, known for his work with lack holes and relatively cheap and the author of several popular books including a brief history of time. he died peacefully at his home in cambridge. this statement released by his he said that we are deeply saddened our great father passed away today. he was a great scientist and an extraordinary man whose work and legacy will live on for many years. his courage and persistence inspired people across the world. the statement went on to say it would not be much of the university was an home to the people you love. we will miss him forever. he has also been described as the most talked about scientist since einstein. stay with us. goodbye. hello there.

plenty to talk about in the weather story for the remainder of this week. we closed out yesterday in the south—west with a beautiful sunset. however, u nfortu nately, that's the place today where we will see some of the wettest and windiest weather courtesy of an area of low pressure moving in from the atlantic. it is bringing quite a lot of heavy rain and gale force winds to parts of portugal and spain. this low will sit out in the atlantic and influence the story for the next few days to come. good news, a southerly wind will bring milder air across the country so if you managed to escape the rain and get sunshine, it will feel quite pleasant. quite a west—east divide with our weather today. central and eastern areas seeing the best of the sunshine and further west will see increasing and strengthening winds and rain, some turning heavy as we move through the middle of the day. gale force gusts through the isles of scilly, up into cornwall and affecting south wales as well. eventually, we will see the rain pushing steadily northwards

into lunchtime into northern ireland and western fringes of scotland. there is a level of uncertainty as to how far inland that frontal system will turn as we go through wednesday but central and eastern areas should state dry, bright and sunny. we should see highs peaking at 14 which will feel quite pleasant with the sun. moving into thursday, we still keep the winds across the south—west noticeably and a weather front making slow progress north and east. behind it, sunny spells and scattered showers. some could be heavy and possibly thundery. we keep the mild air down to the south but things are starting to change into the north—east. as we move into friday, more of an easterly breeze driving in a few showers and these will turn wintry to higher ground chiefly on friday but milder air still sits over england and wales for one more day at least. as we move out of friday and into saturday, under the influence of high pressure yet again, into scandinavia, and circulating around that high,

we will continue to see that easterly wind returning. not quite as extreme as last time but nevertheless it will be noticeably colder as we head into the weekend and there is a risk of snow showers falling at lower levels across eastern parts of england through the day. it is worth bearing in mind as we head into the weekend, there is the potential to see the return of some snow which could cause some issues. keep watching the weather forecast. this is bbc news. the headlines: professor stephen hawking, the world famous physicist and author of many bestsellers, including a brief history of time, has died at the age of 76. he became possibly the most talked—about scientist since einstein for his

ground—breaking work with black holes and relativity. russia has ignored a midnight deadline, set by the british government to explain how a nerve agent, thought to be russian made, was used to poison a former spy and his daughter. sergei and yulia skripal remain in a critical condition in hospital. moscow continues to deny any involvement in the attack. us secretary of state rex tillerson has made his first statement since being sacked by president trump, conspicuously failing to thank his boss, or praise his policies. the president told reporters that he and america's top diplomat had a "different mindset" on key issues, including the iran nuclear deal. now on bbc news — hardtalk.