this is bbc world news, the headlines. president trump has said european countries must take back hundreds of is fighters captured in syria and put them on trial in their home countries. if not, he said the united states would be forced to release them. the teenage girl who left britain to join so—called islamic state in syria says she's given birth. shamima begum, now aged 19, is at the centre of a debate about whether she should be allowed return. venezuela's self—declared interim leader, juan guaido, is calling for venezuelans to cross borders and bring humanitarian aid into the country next week. president maduro says the aid is part of a us plot to disguise an invasion. at least nine people were killed when fire swept through more than 200 slum dwellings in chittagong, in southern bangladesh. 50 other people were injured. at ten o'clock tina daheley will be here with a full round—up of the day's news. first it's time for our world.

when the chernobyl nuclear power plant exploded 33 years ago it was the largest ever accidental release of radioactivity into the environment. but what's become of the people who refused to leave the exclusion zone, and the wildlife left behind? victoria gill has been given rare permission to go inside the zone, and the plant itself. surrounding the site of the world's worst nuclear accident, more than 4,000 square kilometres, spanning ukraine and belarus, was abandoned. more than three decades on, in a post—human landscape, nature has taken over. what happened to those who refused to leave? has the truth about this place become lost in

the infamy of the disaster? standing a kilometre from where the nuclear accident happened, we are getting less of an external dose of radiation than on the flight over? three times less than what we got on the aeroplane coming over. all: i love you. what does the future hold for those who still live in the shadow of chernobyl? 130 kilometres north of the capital, kiev, part of ukraine has been cut off for more than 30 years. heading for the exclusion zone, which is quite exciting. sort of a forbidden place kind of shrouded in mystery. this is a controlled zone, a contaminated area almost

twice the size of london, that we have special permission to visit. we are going into the epicentre of an explosion. it happened on the 26th april 1986, a day the world never forget. archive: the soviet union admitted this evening that there has been an accident at one of its nuclear power stations. archive: perhaps the worst accident in the short history of the world's nuclear power industry. we're taking a tour of the chernobyl nuclear power plant, with our guide. safety regulations mean we have to protect our clothes from radioactive dust. if know one rule, if you follow all rules, you do not break rules, everything will be ok. 28 year, a little bit more passed after my first coming to chernobyl npp and everything is ok.

god bless us. with us is a scientist whose life's work has hinged on that one terrifying night in soviet history. how long have you been studying the aftermath of what happened here? since 1990. have you been into the reactor building before? i have never been before. reactor number four still lea ks radiation so it's entombed by a steel confinement structure, containing remains that would blast it apart. this is footage captured beneath that dome. a now solidified mass of concrete and nuclear fuel is still so radioactive that people can't be under here for more than a few minutes. but the plant continued to produce power until the year 2000, and the neighbouring reactor

is still being decommissioned. few visitors are allowed in here but we have been given permission to look inside. alarm beeping. is your alarm going off? that is my alarm going off, yeah. what is it? what have we gone up to? we have got up to 1a, and i set the amber warning to be at 10. right. so we've just gone over that. throughout our trip, jim is carrying a dosimeter, measuring the radiation dose we are getting every hour. we're still well below the level where i considered we didn't want to get to. but i am just going to switch it off because we do not want it going all the time. there is a strange atmosphere to this place. and you're so trussed up, that there's a nervousness, there's a fear to that, i think. my heart is beating quite fast, actually. it was 1:23am when engineers cut power to parts of the chernobyl plant number four reactor.

they were testing what would happen in the event of a blackout. what they did not know was the reactor was already unstable. it wasn'tjust one person, it was a whole chain of people, from the reactor design people to the people operating it, to the whole kind of safety culture. the shutdown slowed turbines that drove a flow of cooling water to the reactor. the reactor collapsed, the reactor collapsed, everything collapsed and when this engineer pushed the button to stop the chain reaction, big pressure of water, steam was coming from the bottom. a steam explosion blew the lid off the reactor, exposing the core to the atmosphere. air fuelled a fire that burned for ten days. that initial explosion killed two people. in the days that followed, emergency workers rushed in.

people known as liquidators were sent to remove highly radioactive material that had been blasted onto the rooves of nearby buildings so it could be swept up and contained. 134 emergency workers suffered acute radiation sickness. 28 died within months, another 19 have died since. some surviving workers today live with skin and eye injuries, from working in that highly radioactive environment. and the impact was not confined to this site or even to this country. a cloud of radioactive smoke and dust was carried on the wind around europe. information emerged only gradually from behind the iron curtain of the soviet union. that cloud though carried the truth of the disaster. the world held its breath. this was the largest accidental release of radioactivity into the environment in the history

of nuclear power production. the cause, who is to blame, are issues still being debated to this day. every so—called accident, incident, concerned with human factor. if there were some defects here in this type of reactor, who was the designer? a robot? no, a man. and if the personnel made some mistakes during that test, who were they, robots? no, the personnel. everywhere we came to one conclusion and that is human factor everywhere practically. today, the consequences of that terrible accident are etched onto this region. within a boundary drawn at a 30—kilometre radius of the plant is the primary exclusion zone.

no—one was allowed to return here to live. but just beyond that, captured by an outer boundary, is a secondary zone where people have been left in limbo. narodychi has a population of 2500. tatyana runs the kindergarten. she remembers the evacuation. but the future for these children and theirfamilies is uncertain. narodychi has some of the lowest

radiation levels in the exclusion zone but it is still officially designated contaminated and that means no agriculture is permitted and nothing new can be built here. so, could the secret for a new start for narodychi be hidden in the abandoned primary zone? for many it is a frightening place but in the decade since the accident hundreds of scientists have worked here, forensically examining chernobyl‘s aftermath. we're going to meet a true exclusion zone expert. dr sergey gashchak came here in the immediate aftermath as one of the thousands of liquidators.

he is now a scientist. although it is not legal to live here permanently, he still works here from this previously abandoned house. this is a proper field station then. you have lockers for everybody‘s kit, somewhere to leave boots. yeah. this is very organised. is this a map of the exclusion zone? yeah. the red are the hotspots? yeah. where is the nuclear power plant? this is the power plant. for this international community of scientists, the zone is a vast laboratory, allowing them to measure how a landscape recovers from nuclear catastrophe. altogether, this is the lightest protected area in europe by a long way. they eat, sleep and discuss their work here but their days are spent out in the field. today, with the research team, we are looking for wildlife and, following sergey, we eventually come across one of many now desolate villages. it has become a strangely rich habitat and a place sergey seems totally at home.

i am a feral man. yes, you're a feral man! laugh. sometimes i see my family not so often. it's just completely taken over. it's why these villages have become hubs for where some of these ecological studies can be done. because this is just a totally different place. it is not a village any more, it's sort of a rewilded landscape. inside some of these houses, it's still apparentjust how quickly people had to leave. here we can see someone's coat. yes, yes, absolutely. but some of what people left behind — through farming and gardening — has turned into provisions for wild animals. people, before the accident, introduced here a lot of plants. also, they fertilised the soil.

and the soil in the villages is a little bit richer than in the surrounding areas. that is why — they have started to observe higher levels of diversity of animals. we have wolf. just outside the village there are some obvious signs of animal life that moved in when people moved out. you want to see wolf faeces. we have fresh wolf faeces. jim smith is with sergey to check cameras and audio recorders that have been silently monitoring the wildlife. all these years combining the tracking of animal populations and measuring the contamination suggests wildlife is now thriving in a place that many had assumed to be toxic. yes, the exclusion zone's contaminated, but if we were to put it on a map of radiation dose worldwide, only the small hotspots would stand out.

natural radioactivity‘s all around us. it varies from country to country, from place to place. and most of the area of the exclusion zone gives rise to lower radiation dose rates than many areas of natural radioactivity worldwide. it may seem strange that most of this wilderness, that was created by a nuclear disaster, has similar levels of radiation to many parts of the populated world. but being here, surrounded by nature that doesn't observe any boundaries of checkpoints, it actually feels that life is flourishing. apart from glimpses on camera traps, though, i am yet to get close to any of chernobyl‘s wildlife. dr marina is following an unusual experiment. in 1998, zoologists released a herd of endangered wild horses

here in the hope they'd graze away overgrowth and reduce the risk of fire. marina's just spotted a whole herd. these are the przewalski's horses. going to see if we can get a little tiny bit closer. they're a productive herd. so they have adult females, several cubs. several babies, foals. yes, ah, some of them are one years old, some of them are two years old. these animals are native to the open plains of mongolia, but marina's work is revealing some unexpected behaviour that's helping them thrive here. they use the abandoned buildings, because they are avoiding mosquitoes and heat and wind inside. so they're adapting to the exclusion zone? yeah. they were laying and sleeping inside. so they have really good

adapted to this place. they're really using the buildings. amazing. wildlife may be making the most of this place, but not every village was left for natures to reclaim. we're deep in the permanently abandoned zone. and some people still live here. victoria. nice to meet you. today is maria's 78th birthday and she's made us breakfast. oh wow. thank you. up to the day of the accident, this had been the only home she knew.

her family then travelled back across a then patchily enforced boundary. they refused to abandon the place. maria and her neighbours make up a remote community ofjust 15. a tiny village reclaimed after the disaster. the residents of this village are amongst just 200 self settlers who returned and stayed. the vast majority who lost their homes in the exclusion zone have no hopes of ever coming back. almost 50,000 of them

lived here in pripyat. this was the soviet dream town, purpose built for workers at the power plant. it was evacuated overnight. no residents were allowed to return. just a few kilometres from the plant, this is in one of the zone's hotspots. and after the city was permanently abandoned it gradually turned to ruin. but in recent years, human activity has come back. pripyat has been deemed safe to visit for short periods and is now a tourist destination. 60,000 people came here last year, keen to witness the decay. chernobyl was number one on the list. because it's, like, something that was in the news a lot when i was growing up as a kid. so it really took on the imagination. i wanted to see what it was like. it is sort of the post—apocalyptic environment, which,

i think, is very scary. the sense of danger here is now a selling point. but should we fear this place? that is a question only the decades of research can answer. 0n the dry bed of what was the reservoir providing water to cool the nuclear reactors, we've come, with jim, to meet this team. we will just fly with the helicopter to look at the plant area, collecting samples of water, soil. he first came here just three months after the accident. his work helped shape the exclusion zone. this is more than half of my life. in the early stage of the accident, the most important was to understand what is the extent.

to draw up the first map... to draw up the first maps, yes. then, of course, much later, as we know, the pattern of contamination is significantly different all over this area, yes. and in this spot, with the help ofjim's dosimeter, it's clearjust how much the contamination varies and how much this place has changed. so here, standing essentially in the cooling pond of the nuclear power plant, a kilometre from where the nuclear accident happened, we are getting less of an external dose of radiation than on the flight over. three times less than what we got on the aeroplane coming over. so, what could that mean for the outer zone? for narodychi? this is a community on the brink of change. the objective is to support and pray...

jim and his colleagues are here for a meeting that could remove this district from the exclusion zone. meaning they could start farming and building again. all of the stakeholders are here, representatives of the local community, the administration, those who run the exclusion zone, hopefully that agreement will be hammered out today. many here still fear chernobyl radiation, how it might affect their and their children's health. long—term impacts, though, have been hugely complicated to unpick. estimates of cancers directly caused by the radiation range from a few hundred cases to many thousands. the contamination is known to have caused 5,000 people, who were children at the time, to develop thyroid cancer. the vast majority were treated and cured. among numerous reports of birth defects and other health problems, it's just not clear if any were linked to radiation. what is conclusive, according to the world health organization,

is that people's mental health has been damaged by fear of radiation and the disruption to their lives. this meeting could lift restrictions that this community has lived with ever since the accident. how did today go, do you think? we are certainly in agreement here that there needs to be change. so the next step is to communicate with the politicians, tell them what our scientific conclusions are, tell them what the narodychi district want, and we hope that they will take action. what's finally on the horizon means that these narodychi's children may no longer be the children of chernobyl. if that political agreement can be reached, the next generation here could shape its own future. that disaster still casts a long

shadow here and what happened in 1986 will always be a feature of this place, but the research that's being carried out here shows that over 30 years the situation has changed and now, perhaps, for the sake of people who live here, it's time to move forward. hello, over the weekend we had

temperatures in the mid—teens and a bit of rain but not much at all over the week ahead. there will be some more rain coming in and it will mainly affect the northern half of the uk and later in the week those temperatures will climb even higher. right now we have some cooler air coming in from the atlantic together with those shower clouds and that is behind that band of clouds. that gets stuck across east anglia and the south—east and we will see some rain and drizzle developing as well but away from here, brighter skies, some sunshine and showers, lots of them in northern ireland, western scotla nd them in northern ireland, western scotland and cumbria. they will be heavy, potentially with some hail and thunder and it will be pretty windy, strong to gale force gusts likely and temperatures in the north—west with those showers back down to 9 degrees. elsewhere, typically ten or 11. still mild for the time of year, not as mild as it has been. all the showers in the north around that low—pressure get pushed away overnight, the rain on

that front gets pushed from the south—east and things quietened down as we await the arrival of the next system as we await the arrival of the next syste m fro m as we await the arrival of the next system from the atlantic. a chilly start on tuesday, some pockets of frost around. a bright start, hazy sunshine, quickly it will cloud over from the west and we get rain in northern ireland, late into western scotland. south—westerly breeze is, quite breezy on tuesday, still temperatures between nine and 11 degrees. it looks like those fronts will not push into the south of the uk, they may mainly affecting northern areas. there might be some heavy rain overnight into wednesday morning over the hills of western scotla nd morning over the hills of western scotland and the cumbrian fells. most of the rain pushes a way out into the north sea towards scandinavia, scotland and northern ireland become drier and brighter and we are left with some patchy rainfor and we are left with some patchy rain for northern england and north wales but still dry in southern england, the midlands and south wales with temperatures back up to 13 degrees. towards the end of the week, the next system comes in with this looks like it will be kept to the west of us because that high

pressure is dominant and it is starting to build in across the uk. light winds in england and wales, a chilly start, mist and fog patches and some sunshine. a bit more cloud in the breeze for scotland and northern ireland but all it was on thursday should have a dry day and the temperatures are rising everywhere. 13—15d. they are climbing later in the week as well and continue to climb on friday. a week with the front in the far north—west should get blown away by the strong winds, a dry day for the most, spells of sunshine and some morning mist and fog where the winds are light but the temperatures are up are light but the temperatures are up to 15 or even 16. into the weekend, temperatures might reach 18 degrees in the sunshine but equally, there might be some more mist and fog around. that is because the position of the high pressure, at the centre of it, that is moving. at the centre of it, that is moving. at the moment it is across the central pa rt the moment it is across the central part of europe and then it shifts to come to rest right over the uk so

the winds become lighter, the skies will be clear at night, some mist and fog but we are still in the milder air, on the right side of the jet stream. we have and a maker block, shown by the position of the jet stream and that pattern is difficult to budge. this is what it means for the outlook, high—pressure, dry, the days will be quite mild, maybe not as mild, the knights will be quite chilly and there might be some morning mist and fog. goodbye. a british teenager who ran away to join the islamic state group in syria says she's given birth to a boy. shamima begum's family has asked the british government to help bring their daughter and her baby home. primarily, they'd like the government to recognise its responsibility to a now one—day—old child and to extend every help that can be given to have that child repatriated to the uk. also tonight: passengers left stranded by the collapse of flybmi are told to make their own way home.

theresa may urges conservative mps to sacrifice their personal preferences and back her brexit deal. we have a special report from venezuela on the worsening humanitarian crisis there.