this is bbc world news. the headlines: police in the us state of california say a man has been detained for questioning in san diego after a shooting incident at a synagogue. there are reports of some injuries. sri lanka has banned two islamic groups linked to the easter sunday bomb attacks, as security forces say six children were among 15 people killed during a police raid. the operation followed a gun battle with security forces. the united nations says some of the villages hit by cyclone kenneth in northern mozambique have been entirely wiped out. it folllows an aerial assessment of the area. the uk government is being investigated over its decision to cancel the visas of thousands of foreign students accused of cheating in english exams. there are now claims that

many of the accusations were unfair. at ten o'clock ben brown will be here with a full round up of the day's news. first on the bbc news channel, it's our world, asking who was to blame for the chernobyl nuclear power plant explosion 33 years ago? 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're 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're 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's 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, stanislav. safety regulations mean we have to protect our clothes from radioactive dust. i know one rule. if you follow all rules, you don't break rules, everything will be ok. and 28 year, a little bit more past 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 ever been into the reactor building before? i've never been before. reactor number 4 still leaks radiation, so it's entombed by a steel confinement structure containing remains that were blasted 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've been given permission to look inside. alarm beeping. is your alarm going off? that's my alarm going off, yeah. what is it? what have we gone up to? we've gone up to 1a, and i set the amber warning to be at10. right. so we've just gone over that. throughout our trip, jim is carrying a dosimeter, measuring the radiation dose we're getting every hour. we're still well below the level where i considered we didn't want to get to. but i'm just going to switch it off because we don't want it going all the time. there's 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's beating quite fast, actually! it was 1:23am when engineers cut power to parts of the chernobyl plant number 4 reactor.

they were testing what would happen in the event of a blackout. what they didn't 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. airfuelled 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 roofs 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 wasn't 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. the town of narodychi has a population of 2,500. 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's still officially designated contaminated. that means no agriculture is permitted and nothing new can be built here. so, could the secret to a new start for narodychi be hidden in the permanently abandoned primary zone? for many, it's 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's now a scientist.

although it's not legal to live here permanently, he still works here from this previously abandoned house. oh, 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 hot spots? 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 largest 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're looking for wildlife and following sergey, we eventually come across one of many now desolate villages. it's 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. yeah, sometimes i see my family not so often. it's just completely taken over. which is why these villages have sort of become hubs for where some of these ecological studies can be done, because this is just a totally different place. it's not a village anymore, it's sort of a rewilded landscape. inside some of these houses, it's still apparent just 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 the surrounding areas. that is why, according to our study, 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 wanted 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 or 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 over growth and reduce the risk of fire. marina's just spotted a whole herd. these are the przewalski's horses. gonna 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 be 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, ithink, 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 would 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 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. thanks for joining hello. thanks forjoining me. it's time to have a look at the weather for the coming days. so for the weekend has been very blustery, we will talk about storm hannah, but as far as the week ahead is concerned,

there are signs the weather will warm up there are signs the weather will warm up a there are signs the weather will warm up a bit before it calls off again and then maybe it warms up once more. up and down for the coming days. this is the storm we had in the last 2a hours. it barely isa had in the last 2a hours. it barely is a strong, pretty rough across parts of south—western ireland but the low pressure on saturday, sunday it will have moved out into the north sea. to the south, high pressure is building but what we will find in the wake of the storm isa will find in the wake of the storm is a bit of cool air coming out of the north—west before warm air wins and comes out of the south—west. sunday is looking much better across the uk, the winds are lighter, there is more sunshine around, not clear blue skies but it is going to feel a lot better. temperatures on sunday will some 5 degrees higher for most of us, 15 degrees in the south, 16 in the lowlands of scotland compared

to seven to 10 degrees during the course of saturday. if you are out sunday evening, the weather is looking fine, a fine into the day with clear skies. for monday, there isa with clear skies. for monday, there is a weak weather front approaching the uk. that means there is not a lot of cloud, not an awful lot of rain, just if you splits and supports that are affecting the south—west, may be wales, northern ireland but the vast majority of the country should have a fine day and the afternoon is looking fine as well. the weather will be warming up a bit, temperatures in central scotla nd a bit, temperatures in central scotland up to 18 degrees on monday. here is a look at tuesday and spot the difference really, still a week weather front across western areas. some rain to parts of northern ireland, although this is uncertain but look at these temperatures, mid to high teens across uk wildly. a su btle to high teens across uk wildly. a subtle difference as we head into wednesday. week weather front ‘s and

a weak breeze of the atlantic will bring slightly cooler conditions to some north—western parts of the uk, increasing amounts of cloud mid week and you can see spots of rain here too. not a dry day on wednesday but most of us will have dry weather. temperatures around 12 to 1a degrees in the west of the country, 18 in the far south—west. 0n in the west of the country, 18 in the far south—west. on thursday notice high pressure is trying to build from the south—west. low pressure here in scandinavia means the winds are blowing out of the north—west. it is not a one direction, but it means the weather fronts will be pushing into the uk so fronts will be pushing into the uk so cloud and spots of rain, maybe 13, 14 degrees but with the high pressure trying to nudge into southern areas it should not be too bad, temperatures around 16, 17 degrees. friday and into the weekend we should see winning as it starts to build across the uk and keeping the weather front is out at bay in

the weather front is out at bay in the next weekend, and into next week with high pressure building, there should be a fair amount of sunshine and it looks as though things will be warming up, so on the whole, the outlook is not looking bad at all. goodbye.

this is bbc news i'm martine croxall. the headlines at 10pm: sri lankan security forces have detained the wife and child of the man believed to be the mastermind behind the wave of bomb attacks on easter sunday. the home office is being investigated after they revoked the visas of 30,000 foreign students over claims they cheated in an english language exam. the labour party is to change its european election manifesto leaflets, saying it may support another referendum on any brexit deal. northern ireland politicians are being urged to deliver on power—sharing by the priest who received a standing ovation at lyra mckee's funeral. top flight for the canaries — norwich city secure promotion to the premier league. and at 10:30 and again at 11:30, we'll be taking an in—depth look at the papers with our reviewers john stapleton and benedicte paviot. stay with us for that.