this is bbc news. i'm annita mcveigh. the headlines at four: hundreds of thousands of people across america are taking part in rallies calling for tighter gun controls. this is the scene in washington — where survivors of the school shootings in florida are taking part in the rally, dubbed "march for our lives" tributes are paid to the policeman who died of his injuries after swapping places with hostages during yesterday's terror attack. owen smith says he'll continue to argue against brexit, despite being sacked from the labour front bench over the issue. of spectators to the london river's banks, with people coming to watch this year's boat race is expected to bring in thousands of spectators to the london river's banks, with people coming to watch both the men's and women's races. and in half an hour in dateline london, jane hill and the panel discuss whether it's time for tougher regulation of social media, following the row over cambridge analtyica. good afternoon and

welcome to bbc news. hundreds of thousands of demonstrators have gathered in cities across the united states as part of the ‘march for our lives‘ movement. our correspondent gary o'donoghue is at the main rally in washington: things are really starting to hot up here, as you can imagine. people are waiting for those speeches to begin. we know there will be a whole lot of teenagers speaking this afternoon. all of them will be under 18. there are no adults invited to speak at this event, and they will be making some impassioned pleas for greater gun control laws. it is rallies like

this that have been happening all over the country, and of course, down in florida too, the scene of the parkland shooting on valentine's day, when 17 people lost their lives. here is what some people have been saying down there from the different generations. my classmates andi different generations. my classmates and i lay helplessly on the floor, feeling and hearing rapid gunfire. asiam feeling and hearing rapid gunfire. as i am aware that the horrific tape that plays in my head will never be rewound, i am aware that the need for change is overdue. change was due before 17 lives were taken but i acknowledge that change comes with time, but when time is so precious, it is hard to wait. it is time for an immediate change. alex's death could have been prevented. all the 17 beautiful angels' lives could have been prevented. alex was

mortally wounded by gunshots that came through his classroom door while he was working on an english paper with three of his friends. that monster never entered alex's classroom. if the doors had just been bullet— proof classroom. if the doors had just been bullet—proof under windows, alex and many others would still be alive today. some impassioned words down there in florida, which i'm sure will be echoed on this stage behind me in the coming minutes as those speeches get under way. let me bring ina those speeches get under way. let me bring in a guest who is with me, sarah from pennsylvania. why did you have to be here today? sarah from pennsylvania. why did you have to be here today7|j sarah from pennsylvania. why did you have to be here today? i came here because as a student i should not fear being inside my school, and i am tired and angry with my government and their inaction at the moment. even though i am too young to vote, i know what it means to be a responsible citizen. i am here to

campaignfora a responsible citizen. i am here to campaign for a change. were you inspired by the students from parkland? their words have resonated with students all over the country. do you think this movement was waiting to happen?” do you think this movement was waiting to happen? i do think so. i think it has been waiting and i think it has been waiting and i think the students have been brave and courageous enough to speak up and courageous enough to speak up and have sparked this movement.” think a lot of students around the world will think... they won't understand the process you have to go through as an american student, when you have practices for school shooters, don't you? yes, we have lockdown drills, as we call them, where we practice a few times a year, and basically we hide in the corner of the room where you can't be seen through any windows. and you have to remain completely silent. what sorts of change do you think is realistic, because guns won't disappearfrom america. realistic, because guns won't disappear from america. absolutely

not, and i don't think that is what people are asking because of the second amendment right. i think we're looking for some common—sense gun laws, meaning gun control, where people who have been reported mentally ill should not be able to get their hands on a weapon. weapons design for war should not be in the hands of civilians. congress did pass some measures in the spending bill yesterday, some extra measures for school security. what do you think of the idea of arming teachers? not a good idea, and all the teachers i have spoken to about it don't want to be part of that because it is not theirjob. i could understand having an extra police officer in the school, but it is not thejob of a officer in the school, but it is not the job of a teacher to be a police officer, essentially. it's theirjob to educate us and that's what they should be focused on. sarah, we will let you get back to the march. thank you forjoining us on bbc news. the music has gone quiet, which means the speeches are about to begin. the estimates of the numbers of people who will be at the march vary

wildly, frankly. 500,000, tens of thousands. we will find out at some point. back to you in the studio for 110w. gary 0'donoghue in washington. well — hundreds of people have attended demonstrations here in the uk — in solidarity with the protests in the united states. campaigners gathered at the new us embassy in south london this morning — to back calls for tougher gun controls. a demonstration was also held outside the us consulate in edinburgh — where speakers included the family of a victim of the dunblane school massacre in 1996. in other news — theresa may has joined those paying tribute to a policeman who died after switching places with a hostage — during an attack on a supermarket in southern france on friday. lieutena nt—colonel arnaud beltrame was shot by the gunman in the small town of trebes, from where gavin lee reports. tributes of remembrance and gratitude for lieutenant

colonel arnaud beltrame, the heroic officer that secured the release of hostages by taking their place, and ultimately, losing his life. he was one of the first at the scene of the super u supermarket in the southern french town of trebes where dozens of french shoppers were held by an islamist extremist gunman. during the siege, two people were shot dead, 16 were injured. 0thers told reporters how they escaped. translation: i went in the freezer with a dozen other people. then we opened a door at the back, there was a small room. an anti—panic room. we pushed it and we were out. translation: he ran after me. why he didn't shoot, i don't know. maybe he ran out of bullets, i don't know. after two hours, the gunman agreed to exchange the remaining hostages with arnaud, who switched from outside negotiator to hostage and left his phone open once inside, which allowed special forces act. when they heard shots, they moved in to kill the gunman. this morning, the french interior

minister gerarad collomb confirmed arnaud beltrame had died overnight, adding that france would never forget his bravery and sacrifice. forensic teams are working here inside the supermarket. and as the investigation begins into yet another terrorist attack on french soil, we're starting to learn more details about the attacker, 25—year—old redouane lakdim, a moroccan national living locally who had been in the sights of french intelligence services. but ultimately, they didn't consider him a terrorist threat. the immediate focus will be on determining whether redouane lakdim acted alone or had been to syria and had links to so—called islamic state. three other victims of the attack are expected to be named later today. gavin lee, bbc news in the south of france. social media is flooded with tributes to the french police

officer, arnauld beltrame.. including from the french president, emmanuel macron. on twitter, mr macron says he's sending his sincere condolences to the police officer's family, and calls on everyone in france to honour his memory (ani) here, the prime minister theresa may says she is saddened to learn that the officer has died. she adds ‘his sacrifice and courage will never be forgotten.‘ there have also been a number of tributes from those involved in british policing. stirling police have tweeted a picture of the gendarme, with the caption ‘in memory of arnauld beltrame', #homage. lincolnshire's police and crime commissioner markjones says ‘so sorry to hear the exceptionally brave french police officer arnaud beltrame has died after swapping himself with a hostage taken by a terrorist yesterdsay. this time, france, next time, who knows. our police run towards danger we run from, and we should never forget that. a policeman has been killed in a car bombing in the egyptian

city of alexandria. the interior ministry said the bomb targeted the city's security director, whose vehicle was passing by at the time. he escaped unharmed but four other people were injured. the attack comes two days ahead of the presidential election. public health england have issued fresh precautionary advice to anyone in salisbury who may have come into contact with the nerve agent used to attack sergei skripal and his daughter yulia. the advice is relevant to as many as 500 people who may have visited the pub and pizza restaurant between the time of the poisoning and before they were closed the following night. our correspondent kathryn stanczyszyn is in salisbury. it isa it is a busy saturday here than the last few. it is said that businesses

and shops have been suffering because people have been staying away following the poisoning. there is still a police cordoned in place for i is still a police cordoned in place foriam, is still a police cordoned in place for i am, at the park where sergei skripal and his daughter were found slumped unconscious on the 11th of march. a week later, public helping with issued advice to anyone who had either been in the restaurant they had dined in or the pup from the sunday afternoon till the monday evening, saying anyone who had been in those locations needed to wash their clothes because of the danger of prolonged or repeated exposure to the nerve agent used, and they said it was precautionary. they were saying if the clothes could not be washed, back them up and keep them safe somewhere. the latest advice from public health england yesterday was talking about possessions and it said that if you have those dry clea n said that if you have those dry

clean only clothes or other things bagged up, please contact wiltshire council, who will then arrange to come and pick up those possessions to be destroyed. they haven't confirmed that, but that is very likely what they will mean, because they are talking about compensation and they say you will be paid for whatever those items are. people in salisbury have been telling me today that they are a bit concerned that this advice has now come out two weeks after that initial advice, because if that was the case, why not tell people right then that those possessions were going to be picked up? generally, most people are going about their business as normal today and saying they are just trying to carry on life here. has there been any more reaction from russia to the investigation here? we are hearing reports from moscow in the last hour from reuters, that moscow has said that europe is being unpredictable and aggressive. of course, it is following the backing

that eu leaders gave to theresa may during the week saying it was highly likely that russia was behind this poisoning. that is why the eu recalled its ambassador from poisoning. that is why the eu recalled its ambassadorfrom russia, and now it says it is thinking about next steps. these reports from reuters say that moscow says it is uncomfortable about that european sta nce uncomfortable about that european stance over the poisoning, and it's unpredictable, aggressive behaviour. this is the reality we have to live with, according to a kremlin spokesman. the former shadow northern ireland secretary, owen smith, has said he will continue to oppose labour's stance on brexit after he was sacked for calling for a second referendum on the terms of the final leave deal. mr smith said he believed jeremy corbyn wanted to adopt a more euro sceptic approach — which he believed would damage the country's economy. he said he was speaking up for the majority of labour party members on the issue of brexit. labour members have been

speaking out strongly. is we passed a resolution at conference last year that was, frankly, exactly the same as what i said in my article. and members across the country have been contacting me before and after my sacking to say that this is what they believe. the vast majority of labour members support us taking a much tougher stance against brexit, and that's what i think jeremy corbyn and the leadership of the labour party need to do. the labour mp for derby north, chris williamson, is a former shadow minister, and a close ally of the labour leader. he told us mr corbyn was right to fire owen smith. owen smith wrote an article that was against the labour party settled position in relation to brexit, and on that basis, if you will speak against the collective view of the shadow cabinet, then i'm afraid you have to go on to the backbenches. i stepped down from the front bench

myself a couple of months ago because i wanted to speak on a wider range of issues. i wasn't able to do that whilst being on the front bench, and so i decided to be an out rider, if you like, on the backbenches, and that is what owen can now do for the peak and speak up for the things he feels passionately about. when you take a front bench role, you have to accept collective responsibility. that was chris williamson, the labour mp for derby north. a reminder that this coming thursday, it marks one year to go before the uk leave the eu. throughout the week, we will put your questions to a range of experts. it is for 15 pm. the headlines: hundreds of thousands of

demonstrators are attending rallies across the united states as part of the march for our lives movement. tributes are paid to the policeman who died of his injuries after swapping places with hostages during yesterday's terror attack — president macron says he was a hero. owen smith says he will continue pushing for labour to change its position on brexit — despite being sacked from the shadow cabinet. in sport, formula 1 is back with thrills and spills in melbourne. lewis hamilton takes pole position with a sensational lap to league qualifying for the australian grand prix. valtteri bottas crashes out. ina prix. valtteri bottas crashes out. in a weekend of international friendly matches, northern ireland beat south korea 2—1. and more poor weather in auckland ruins england's first test against new zealand. only 17 balls were bold and four runs scored before play was abandoned. england are 175 runs

behind. i will be back with more at 5:30pm.join me behind. i will be back with more at 5:30pm. join me then. oxford is aiming for a fifth win in six years against cambridge in the men's boat race this afternoon. the cambridge women's crew is hoping for a repeat of last year's victory, when they take to the water just after 11.30. the men's race follows — getting under way just after 5.30. our sports correspondentjohn watson is by the river thames in putney for us. what sense do you have got of the final preparations for the teams as we get very close to the start of the women's race? absolutely, we are only 15 minutes away now from the start of the women's race, so both of the teams have been going through final preparations here on the water. they tend to head out about 45 minutes before the race begins to warm up,

45 minutes before the race begins to warm up, go 45 minutes before the race begins to warm up, go through final preparations. it is advantage to cambridge, they won the toss and they have selected the south side of they have selected the south side of the river, the surrey side, which gives the advantage of the inside of the big bend that awaits them on the course to come. historically, it seems that the teams that select the south side of the river do have that advantage. statistics suggest that they will have that advantage going into the race ahead. cambridge will look to try and build on that big win last year. they completed it in a course record, so it will be hard to top that as far as the women's race is concerned. the men's race follows them one hour later. oxford, despite having won four of the last five races, they won last year in impressive style, it is cambridge you have the advantage again. they have also won the toss, choosing the south side of the river. it is fair to say, cambridge were the favourites for the men's race coming into this. they have the more

experienced crew. james n is in the numberfour seat, experienced crew. james n is in the number four seat, and you experienced crew. james n is in the numberfour seat, and you can't experienced crew. james n is in the number four seat, and you can't miss him, at six foot ten he is the tallest man to ever row in the boat race. a big advantage lie as well. a lot of power and pace in that cambridge crew, and they are going in as favourites. oxford are the underdogs, with late changes to their crew. and being the light of their crew. and being the light of the two cruise as well. historically, the heavier of the crews have an advantage going into the race. 15 minutes away from the start of the women's race, lots of people lining this stretch of the riverfrom people lining this stretch of the river from putney to mortlake, around 250,000 river from putney to mortlake, around 250 , 000 spectators river from putney to mortlake, around 250,000 spectators here to watch the boat race this afternoon. john, thanks very much. six england football fans are still being held by police in amsterdam. they'd travelled to watch the national side play a friendly against the netherlands. in total, a hundred england supporters were detained, but most have been released.

online shopping is causing roads to be clogged up and worn out by delivery vans, councils have claimed. the distance travelled by light goods vehicles in britain has risen by almost 20% since 2011, according to the local government association, whilst average speeds on a—roads have fallen by 4% since 2014. the amount spent on online retail has increased by 23% in a year, according to the most recent data. a rescue operation to try to save a large group of wales stranded on a beachin large group of wales stranded on a beach in western australia has come to an end. sadly, all but five of the 150 whales have died despite the effo rts the 150 whales have died despite the efforts of conservation of —— conservation officers at hamelin

bay. for hours, dozens of volunteers supported by vets and wildlife officials tried to save survivors from a stranded pod of short finned pilot whales. about 150 were found at hamelin bay in western australia. most were dead by the time help arrived. but rescuers using heavy machinery did manage to return six animals into the water. for us, the biggest concern is them being out of the water and sunburnt, so we've got them covered, and we're trying to keep them as moist as we can. one didn't survive, and there is a risk the others could return to dry land. it's not the first time there's been a mass beaching in this part of the western australian coast. but scientists don't know why some whales appear to be drawn as if by a magnet to the shore. researchers have called hamelin bay a whale trap. they believe the shallow waters and coastline can interfere with the bio acoustic sonar these graceful mammals use to navigate safely. there is a theory that intense wind and waves generated by cyclone marcus that's been

battering parts of northern australia could have disrupted the whales' sensitive guidance system. the dna samples are being taken from the dead mammals to try to understand why so many ended up on the beach. work to remove their bodies is continuing. a shark alert has also been issued by fisheries authorities in western australia, because of fears the whale carcasses may attract ocean predators. phil mercer, bbc news, sydney. almost 30,000 single parent families were made homeless last year, an increase of eight per cent on five years ago, according to new official figures. the housing charity shelter said government figures also reveal that nearly three—quarters of homeless households in england are lone parent families. i've been speaking to the shadow

homelessness minister, who said that private rent prices were too high. around the country, particularly in areas where private rents are particularly expensive and there is competition for private properties, this is something that people are experiencing. and increasingly, they are experiencing that because landlords are unwilling to accept some of the delays around universal credit. i guess everyone listening to this detail in terms of the new survey that's been done can understand the sort of factors that might lie behind a large proportion of homeless people being single—parent families. the official definition of homelessness refers to those in temporary accommodation rather than without a roof over their heads. what is the quality of their heads. what is the quality of the sort of temporary accommodation thatis the sort of temporary accommodation that is out there? if we look at the overall picture, it has more than doubled in the last eight years,

including people who are rough sleeping. we have about four hours -- 4500 sleeping. we have about four hours —— 4500 people sleeping rough on any night up and down the country. when it comes to temporary accommodation, and single—parent families will be placed in that if they find themselves without anywhere to stay, we have heard examples in the house of commons of warehouse style buildings that people have been put into single rooms for multiple children and a parent that are only supposed to be used to a max —— for a maximum of six weeks. and often they are staying in there are up to two years. it is not good for children's ability to learn, their mental health and not good for the whole family setting. part of the problem is that there is an insufficient number of social houses available. the shadow homelessness minister. we asked the government foran

minister. we asked the government for an interview with the homelessness minister, heather wheeler, but she was unavailable. in a statement she said: "government is serious about reducing homelessness and rough sleeping (ani) we're investing £1.2 billion to 2020 to address the issue and next month sees the most ambitious legislation in decades to prevent homelessness come into force. these latest statistics show encouraging signs that our investment and targeted support for local authorities is having a positive impact." the environment secretary michael gove has accused sheffield city council of "environmental vandalism" and has promised to do "anything required" to end the city's controversial tree—felling programme. thousands of trees are being felled as part of a contract the council has signed with a private company to improve the city's roads. campaigners say they are outraged that healthy trees are being cut down and large numbers of police have been deployed to protests. the city council says it is doing "what the majority of sheffield residents want" — and that every tree which is removed is being replaced.

dino sofos reports from sheffield. shouting people in sheffield are really angry. aren't you proud of your city? they've taken to the streets. and they're getting arrested. they're outraged that a private company employed by their council is cutting down thousands of what they say are perfectly healthy trees. the council has signed a contract with the private company amey to improve the roads in the city and to get rid of trees deemed to be dead, diseased and dangerous, which will then be replaced with saplings. part of that contract says that almost half of the city's street trees will be felled, although the council disputes this. although many residents support the felling, there have been ongoing protests. shame on you! the police have stepped in in large numbers. south yorkshire police are like the gestapo. campaigners say they feel intimidated. what are you doing? this woman was arrested on suspicion

of causing intentional harm or distress and will have to go to court. shouting another woman who didn't want us to show her face said her son went to a protest with friends when his school was closed because of the snow, and the police stepped in. as he arrived, one of the police officers says "there's a minor here, call social services". and lo and behold, social services turned up. how does that make you feel? well, it's exactly how they want to make me feel. nothing strikes fear into the heart of a parent like a phone call about social services. whose street? our street! south yorkshire police say they have a duty of care when children are present and will always contact their parents and council staff to ensure their welfare. they say the policing of protests comes down to an exercise of balancing competing rights and upholding the law. the campaigners are outraged that the council isn't

willing to negotiate. the leader of the council, julie dore, hasn't responded to my interview requests, so i decided to track her down. julie? bbc news. can we have a word, please? can we have one minute to talk to you about trees? butjulie, the people of sheffield are concerned about why there are police on the streets. they're saying it's your contract. julie, can we talk you?! there's real pressure on the council. some local mps and the shadow environment secretary have urged them to pause the felling. amey say they're willing to talk, but altering the contract would result in practical or financial changes. the environment secretary has been to sheffield and has also called on the council to stop what he calls environmental vandalism. he says the government is willing to intervene. we will make sure we can do anything that is required to stop this. stop the tree felling now, and stop trying to justify a mistaken course of action.

the labour—run council says it's disappointed by mr gove's unsubstantiated comments. meanwhile, the campaign to stop the trees coming down continues to grow. dino sofos, bbc news. you can find more on this story and a longer version of this report on the bbc news website — bbc.co.uk/news in a moment, it will be dateline london. but first, the weather with lucy martin. hello. it feels like spring for many of us do this weekend. some outbreaks of rain and drizzle in devon, but in the north, for northern ireland, scotland and northern england, more in the way of blue skies and sunny spells. a few showers in the north—west and they will persist tonight, some wintry on the high ground. clear skies in the

south—east. some outbreaks of light rain and drizzle, perhaps some patches of mist. it won't be just as killed in the south—east. away from that, the chance of a touch of frost to start the day tomorrow. the cloud will thin and left in the south. brightness developing. there will be good spells of sunshine elsewhere, but somejobs are good spells of sunshine elsewhere, but some jobs are possible in north—west scotland, some wintry. temperatures are around 12 celsius, and a —— the wind is light. a reminder that the clocks go forward one hour tonight. it is the beginning of british summer time tomorrow.