this is bbc news. the headlines — new zealand's prime minister, jacinda ardern, has unexpectedly announced that she will stand down early next month. her labour party will elect a new leader on sunday. ms ardern told reporters that she couldn't find the energy or heart to continue until a general election in october. ukraine's interior minister and two seniorfigures within his department have been killed in a helicopter crash in kyiv. it came down in fog in the eastern suburb brovary, hitting a children's nursery. 1a people died, including a child. a state of emergency is in place in the peruvian capital lima, where there were violent clashes between anti—government protesters and police

on wednesday. buses brought protestors into the city ahead of more action planned on thursday. they're calling for fresh elections. all police forces across england and wales are being asked to check their officers against national databases to help root out corrupt individuals who may have slipped through the vetting process. it comes after a serving officer, david carrick, was found to be a serial rapist. the government has promised reforms that will leave offenders with "no place to hide". our home editor mark easton reports. chanting: no justice! no peace! no rapist police! the reverberations from the carrick scandal continue with police chiefs and politicians expressing their determination to root out misogyny and predatory behaviour from the ranks. sexist police have got to go!

every police officer and staff member in england and wales will be checked against national police databases for any convictions or intelligence that might identify those who have, like carrick, slipped through the net. on monday, he admitted to 49 offences, including 2a rapes against 12 women. the abuse of power is truly sickening. the prime minister spoke of his outrage in the commons this afternoon before meeting the commissioner of scotland yard at a police station in south london. what we want to do is make sure that there aren't serving police officers anywhere, at any stage in their career — or, indeed, staff in police forces who shouldn't be there. the national police database contains a variety of information about people against which those individuals can be rechecked. it's important that we do that immediately and police forces carry that out to identify and root out anyone who's not fit to serve. no—one doubts the damage the carrick case and other recent scandals have already

done to trust in policing, particularly among women, but there is an urgency in the political response because of concerns that without action, public confidence in law enforcement could be damaged still further. carrick was recruited, despite being suspected of two offences against women, and also passed two internal vetting checks. a home office review will look at what went wrong. the mayor of london, sadiq khan, has said carrick should lose his £22,000 a year police pension — a call that has home office support — but it is the loss of trust in policing that will exercise politicians far more. mark easton, bbc news. now on bbc news, extreme conservation: the maldives. i'm michaela strachan, a wildlife presenter with a passion for conservation. for the past 35 years, my work has taken me all over the world.

and in that time, i've seen huge changes, many due to climate change. in extreme conservation, we travel to different countries, meeting inspirational people... hello! ..with new ideas. this time, i'm in the maldives. this seems like paradise but behind all the beauty and the luxury lodges lies a very real and looming threat, and that's climate change, which is literally washing these stunning coral islands off the map. as soon as they realise i'm from the maldives, they're like, "oh, when is it sinking? "i got to get there before it sinks." the maldives needs solutions, and it needs them fast. our islands are eroding at an alarming rate. we depend solely on our coral reefs for income, for protection, and for our survival, as well. i travel across the islands to meet some inspirational people with exciting ideas.

seeing the radical new ways to bring coral reefs back to life, and a completely new, sustainable way of reclaiming much—needed land. this is extreme conservation, the maldives. the maldives is located about 500km south of india in the pacific ocean. —— in the indian ocean. it's made up of almost 1,200 islands that sit within these circular formations called atolls. and it's these low—lying islands that the maldives has become famous for. seaplanes are the fastest

way to get around. but for most visitors and locals, boats are used to island—hop. these islands may be beautiful but they're precariously close to disappearing into the ocean. most of these islands have been affected by erosion and the prediction is that by 2050, 80% of them could become uninhabitable. without coral reefs to protect them, the maldivian islands are in danger of being washed into the ocean. my first stop is fulhadhoo, an island only 6km long and just 250m wide. seeing this sandbag barrier on arrival, you start to understand the battle these islanders are facing.

coral and coral reefs are what makes these islands but they are facing huge challenges, so the first person i'm going to meet is someone who's made it their life's passion to protect and nurture corals. thanks. this island has a population of a few hundred people. it's so thin, any erosion can have a dramatic effect on their lives. hello! i'm going on a field trip with aya naseem and her team. aya is a marine biologist at the maldives coral institute. she's taking me to see one of their coral projects that they hope may offer a solution in maintaining the health of these life—giving reefs. so, for the maldives, all our islands are protected by coral. if you can see, like, where the waves are breaking,

sometimes then, you'll get really big waves coming in. but it all gets dissipated by that whole layer of coral that you see there. by the time it reaches the shore, it's really low impact and it's not going to erode the beach so much. so, the coral reef is an important natural barrier to stop the erosion of the beaches? that's right — it's our first line of defence. so, what's damaging the coral reefs? unsustainable development — that's a big problem. climate change issues with, um...coral bleaching. a bleaching event is when the coral dies en masse due to unusually warm sea temperatures. one of the biggest ones was the first one in 1998, which affected about — more than 90% of our coral. and we did get a lot of recovery but then, these events are getting more and more frequent. so, we had one in 2010 and then, we had another one 2015—16 and now, we're bracing ourselves for another event.

but amid this bleaching onslaught, the team has made an important and unexpected discovery — some of the corals in fulhadhoo have managed to survive. they show high thermal resilience because they've been surviving in — in these conditions and in really shallow waters that leave them exposed at low tide. so, they're now planting more of these resilient corals. growing coral is a bit like underwater gardening. small, fallen—off fragments are collected and attached to these sand—coated steel structures. from there, with a bit of luck, they grow and flourish. it looks stunning! thank you. i mean, already, in six months, it's looking beautiful. how long do you think it will be before that is a full coral reef? i mean, how many years down

the line are we looking? two or three years, we're hoping because already, they've grown so much. yeah. so, around two to three years, you won't be able to see the frames any more, so looking forward to that. you can see from the colours — the blues and the purples — that this is really working. this is what coral should look like. and if they can be kept alive even as the sea levels rise, they can keep pace, grow upwards and protect these islands. but as warm—weather bleaching events become more frequent, the corals get very little time to recover, let alone grow. and bleaching isn't the only threat they face. it's easy to forget that a coral reef is a living thing and just like us, to stay healthy, it needs to eat well. now, we all know the stories of the damage that plastic does to other marine life but, believe it or not, it can also damage a coral reef because it ingests this stuff in the form of microplastics and obviously, that does it no good at all. thanks.

tourism in the maldives has been expanding rapidly since the 1970s. it went from only 60 beds to 60,000. and plastic waste has become an enormous problem. but ground—breaking ways to deal with it are emerging. i'm off to soneva fushi, an exclusive destination for the super rich. but despite all the luxury, this resort is surprisingly a pioneer for ecotourism. where did the vision come from? because it started 25 years ago for you? yes, yeah. so, um...i met my wife when i was still at university at oxford. she'd been to the maldives on a modelling shoot in the early �*80s. so, we came for the first time. it was a very simple destination in those days and nothing was sustainable because they had a very, very tight budget. so, we decided we could do something a bit more unique and different. and so, they did.

rubbish from the surrounding islands is collected and processed here. they try and use every part of a natural resource, like a coconut, and then, as much rubbish as possible is either reused, recycled or upcycled. and guests are invited to take part if they want to. the aluminium cans from drinks become ornaments or door handles. ok, let's see how this has come out. oh, wow — look at that! and how many resorts do you know that have their own glass—blowing studio, where you can turn a wine bottle into a glass and beer bottles into a platter? i think this is what you call high—end artistic upcycling. what they've done here is really impressive. it's inspiring. but you have to remember that this is a luxury resort. there's a lot of finances in this place. and you have to wonder could this be upscaled to use as a production line in other

parts of the maldives? the country is making strides, trying to modernise how it manages its waste. but the reality is even for a luxury resort, what to do with plastic is dwarfed by the threat from the sea. so the maldives have been sinking for thousands of years and it's the live coral that's been keeping us alive. so, even if sea levels don't rise but if the coral dies, then eventually, the core of the islands will continue to sink, so our goal is to keep the coral alive. sonu tells me he's started his own marine research institute on the resort. i've come to meet the scientists who are trying a different approach to nurturing the corals back to life. this is one of the largest coral nurseries in the world. thousands of colonies saved from a nearby site have been planted here.

aki allahgholi, a former banker turned coral specialist, is leading the project. the goal is to produce, basically, 50,000 corals every year to be outplanted into the environment where they are needed. over the next eight years, until 2030, we try to bring back the diversity and the coral cover we used to have about 25 years ago. to speed up the growth, a very low—voltage electrical current is run through the frames. the technology that we apply here is called the mineral accretion technology. it helps the corals to grow faster, they become more resilient and the survival rates are better. the technology has been around for years and is proven but the challenge now is in applying it on a massive scale. many nurseries use these steel frames to grow corals.

thank you very much! bye— bye! take care. but my next destination is experimenting with an alternative approach. i'm on nearby summer island to join the island's dive master, arjan sierink. hi! good to meet you! pleasure! i've heard so much about you! and this is what i've come to see — the world's largest 3d—printed reef. it was made in australia by reef design lab using a ceramic material, and then shipped in small sections to be constructed underwater. took a little while for the corals to get used to the material. they grow slower than the corals. but the corals are very, very strong. a living reef is the most effective natural defence barrier for protecting the islands from erosion.

3d printing allows for rapid testing of new designs to find the best structure for growing corals. the team behind this is now looking to use similar techniques to create other reefs in other parts of the world. as for summer island, this is one of the many different shapes arjan�*s experimenting with. and it's incredible how quickly the wildlife has claimed it as its home. his recreated coral oasis was literally swimming with fish species. we're still pioneering, and there are many, many islands, many projects all over the world, to find out how we can make the corals more resilient. the biggest challenge will be to get the people to realise that something big needs to be done. we have to work together. governments, scientists, and all this together, could be the perfect solution.

so far, i've been looking at why corals are vital to these islands, and i've been looking at some truly inspirational projects that could restore the reefs. after the break, i'm going to be looking at some even more ambitious projects that could just buy these islands enough time not only to save the corals and the islands, but the way of life, as well. i'm continuing myjourney through the maldives, and i'm leaving the idyllic islands behind to travel to the capital, mali. this is a city of 250,000 people crammed into a space more densely populated than manhattan. and it's completely hectic. it's so packed, it's hard to get a sense of how developed it is until you get a little bit of distance. there's not an inch of space left. so much so that they built another island just to house all the people. this is hulhumale, built to cope with an ever—growing population just 15 years ago. but how do you build an island? to find out, i went

on a brand—new one. so, we're standing on an artificial island? exactly. two—and—a—half years ago, - this was a very small sandbank which has been artificially- reclaimed into an island now. and you've reclaimed it by dredging sand from the ocean? we've dredged sand - from the nearby lagoon. and right now, this is the size of eight football fields. - how much sand do you need to do that? we have put in almost the equivalent of 100 i olympic swimming pools. this will soon be a luxury resort. but the trouble with building this way is it massively damages the environment. disturbed sand sediments can smother the very corals that the maldives relies on for protection. the more you dredge, the worse the erosion becomes. to see the effects this is having on the local population, i'm travelling to the island of dhiffushi. there are no resorts here, just simple guest houses.

wow, look at this! you can clearly see that the beach is eroded. the beach shouldn't fall off like that. and apparently, that buoy is where the beach used to be. so they've lost at least 15 metres of beach. that's severe. without the beach, the island has become yet more vulnerable to flooding. so, what do you do when you know your island is going to flood once a year? well, these islanders have got the sandbags out and they've tried to make their own defence barrier. aminat houdar is someone who's lived here all her life and witnessed first—hand the effects erosion is having.

this is dhiffushi school. you can see it's right near the beach. but because of the erosion, it's now flooding. and in fact, last year, the water came right the way through to the other side and came up to about there. and apparently, every year, it's getting worse. so, is there a better way to create new islands and protect established ones? well, perhaps turning to nature will give us the answer. here in the maldives, sandbanks like this appear and disappear. they constantly change size and shape according to the seasons and the ocean's forces. and that really influences the way that the people live and adapt. in fact, you can see

that the locals have really made the most of this particular idyllic paradise. so we have two seasons predominantly in the maldives. one is the south—east and the north—west monsoons. and, you know, literally, during these seasons, we say we see sand shifting and we see sand eroding from one end and then building up on another end. and as a physicist, i thought, you know, can we use this? sarah dole is sri lankan, but has been living in the maldives for over a decade, and has dedicated herself to studying this natural shift of sand to find a way to create islands sustainably. so first of all, you know, we had to study the fundamentals. so at mit, they are studying the fundamental physics and engineering of it. so, like, trying to understand, how does a sandbank actually form?

and that, we've done through satellite imagery and drone footage and, you know, talking to other locals around here, trying to understand the historical data of how sandbanks appear and disappear. five years ago, sarah partnered up with the scientists from the self—assembly lab at mit, the massachusetts institute of technology in the us. the growing islands project is about naturally accumulating sand in the ocean without sculpting or pumping sand, but letting the ocean accumulate it on its own and guiding it, or collaborating with the ocean to promote the accumulation in certain areas where you want it or need it. skylar tibbits and his team simulate the conditions of the pacific ocean and the movement of the sand. they place different—shaped objects in the environment to see which is the best at sand—gathering. our hypothesis is that the reason sand accumulates

in certain areas and not others is due to the relationship of the geometry underwater and the force of the oceans. and so, what we do is we design different geometries, we test them in the lab, we see which geometries accumulate more sand, and then we implement those at full scale in the maldives. this is the beginnings of a new island built on sandbags. and you can see where the sand has accumulated using the forces of nature. it's been here for about two years. it's 20 metres long, it's about four metres wide and about 1.5 metres above the sea bed. another half—metre and it should pop up above the surface and hopefully just keep growing. each time we go, we try different materials, different construction techniques. the reason for that is because we want to try to make

it as scalable as possible. because this is a global problem, it's not only focused on the maldives. so if you really want to have a solution, you need to make it fast, scalable, cheap. and if it works, this sort of deliverable, sustainable solution could be used not only to save the maldives, but many other island nations or coastlines that are also suffering the effects of climate change. fixing it won't be easy. we need to try out new ideas and work together. small is beautiful, and that's how you scale it up. - come here, please. test your innovations, - test your energy solutions, coastal protection and - adaptation measures here, because we welcome it. at my last stop, i'm meeting local children whose futures here in the maldives are very much at stake. what about a triggerfish? zoona is one of the first female diving instructors here. she teaches children about the sea and the marine

wildlife to inspire them to protect it. fishes keep the corals alive, actually. if the coral reefs get damaged and we lose the corals, - it's a loss for the nextl generation and the fish won't be alive. the importance of acting now is not lost on these youngsters. on myjourney this week throughout the maldives, i've met some truly inspirational people. creative minds that are thinking out of the box. and i've seen some ambitious, pioneering projects. but if they're going to make a difference, they need upscaling. they need a collaborative effort, financial backing and political will. and without that, then life in the maldives for the next generation, for these kids, could be very different. but you know what? i'm excited by what i've seen, and i'm hopeful that at least some of these ideas are going to make a difference, and they're going to help the maldives to draw a line in the sand.

hello. this week's weather has been following a familiar pattern — most of the wintry showers have been across northern and western parts of the uk, so some good covering of snow in places, especially into the higher ground. the further east you are in the uk, it's been mainly dry. even though it's been sunny though, it hasn't melted the frost. and we're in the cold air, clearly. there is a change though going into the weekend — milder air toppling in across the north and west of the uk. warmer colours doesn't translate into sunshine, mind you. the blue hanging on a bit longer towards east anglia and the southeast —

so here through the weekend, we'll stay cold. until the weekend, though, it is cold still across the uk. however, where we've had those wintry showers, once we get past thursday morning, they are going to be easing. another widespread and quite hard frost as the day begins, and do watch out for ice after the showers we've had overnight, and there'll still be some falling into the morning — northern scotland, for example, for northern ireland, for wales and for western parts of england. there are met office warnings out there, do check those if you're heading out early on. through the day, most of these wintry showers will fade. a lot of people will have dry weather, but windy with further rain, sleet, and snow pushing back in across northern scotland, adding to the snow we've already got here, and maybe the odd shower brushing the north sea coast of northeast england into the afternoon. temperatures only slowly heading up, but it'll clearly feel quite cold — though, for many away from northern scotland, there is a lighter wind. through thursday night and into friday morning, still some wintry showers across northern and eastern scotland, along some north sea coasts, as well.

but for most, it's dry and clear, though, the chance of getting some fog patches across western parts. and maybe not as cold first thing, but still a widespread frost. and actually on friday, the focus of the showers will be in north sea coastal counties. where we've had most of the wintry showers so far today, it'll be dry and mainly sunny. temperatures maybe a degree or so higher in places, but it's still going to feel cold out there. into the weekend, though, the changes are under way — now i mentioned, although it is turning milder across the north and west, there'll be plenty of cloud around, there will be patchy rain. where it's clearer still, down towards the south and east, the cold air hangs on after a frosty start. there could be a few fog patches reluctant to clear, and perhaps more widespread fog towards the southeast on sunday. temperatures only gradually rising across southeast england, where elsewhere it's turning much milder — 11 degrees, for example, in armagh.

welcome to bbc news. i'm monika plaha. our top stories — in a surprise announcement, new zealand's prime minister jacinda ardern says she will stand down in less than three weeks. i know what this job takes, and i know that i no longer have enough in the tank to do itjustice — it's that simple. ukraine's interior minister is killed in a helicopter crash in kyiv. it came down close to a children's nursery. 1a people have died including a child. translation: we ran - into the street and turning. there were bodies and debris lying around. there was smoke, blood and clothes, and mothers were running. violent clashes between riot police and protesters in peru's capital as thousands continue their calls

for fresh elections.