this is bbc news. our top stories, president biden tells us citizens to leave ukraine now, warning "things could go crazy quickly" britain's most senior police officer is to step down after the mayor of london said he had no confidence in her leadership. canadian truckers block more border crossings to the us in their protest against vaccine mandates, with the economy now counting the cost. a coronavirus scare for the queen. prince charles tests positive two days after meeting the monarch. as with all the medical or health related matters, buckingham palace is saying the absolute minimum. all that royal sources will say is that the queen is not displaying any symptoms of covid.

welcome to our viewers on pbs in america and around the globe president biden has called on all american citizens remaining in ukraine to leave the country immediately. with russia continuing its military build—up along its border with ukraine, mr biden said that he would not send troops to rescue americans, if moscow invaded. let's speak to our north america correspondent, peter bowes. calling on americans to leave and saying things could go crazy quickly. is this an escalation in rhetoric from the president?— president? well, the white house has _ president? well, the white house has been _ president? well, the white house has been telling - house has been telling americans to get out of ukraine for several weeks so this is really the president reinforcing that message and the wide—ranging interview that she gave which coincided with the latest warning not to

travel to ukraine and those americans leaving immediately and also suggesting that if there were a russian invasion there were a russian invasion there would be severe reduced and would not be able to help americans get out of the country and it was put to the president of the country that there could be a scenario and they could send americans in there to help them get out and he gave this explanation as to why he didn't want to see us forces or soldiers in new crop. dancer world war when americans have _ dancer world war when americans have russian started shooting atone — have russian started shooting at one another and we are in a atone another and we are in a different— at one another and we are in a different world than we've been _ different world than we've been. ., ., , ., ., been. not even on behalf of evacuating _ been. not even on behalf of evacuating americans. - been. not even on behalf of evacuating americans. how| been. not even on behalf of. evacuating americans. how do ou even evacuating americans. how do you even find _ evacuating americans. how do you even find them? _ evacuating americans. how do you even find them? i - evacuating americans. how do you even find them? i am - evacuating americans. how do i you even find them? i am hoping that in— you even find them? i am hoping that in fact — you even find them? i am hoping that in fact if he's foolish

enough _ that in fact if he's foolish enough to go when he's smart enough — enough to go when he's smart enough not to in fact do anything that would negatively impact — anything that would negatively impact on american citizens. what — impact on american citizens. what i — impact on american citizens. what i have asked is that american citizens should leave now and — american citizens should leave now and we are dealing with one of the _ now and we are dealing with one of the largest armies in the world — of the largest armies in the world and it's a very different situation _ world and it's a very different situation and things can go crazy— situation and things can go crazy quickly. situation and things can go crazy quickly-— crazy quickly. once again president _ crazy quickly. once again president biden - crazy quickly. once again l president biden expressing crazy quickly. once again - president biden expressing deep concern about what could happen if there is a russian invasion and we are hearing the latest intelligence assessment from this country that russia has the capability with the hundred thousand troops and perhaps more than that on the border with ukraine that the capability is there to launch a full—scale invasion in the next 48 hours with tanks and to be able to get to kyiv. the situation as described by the americans being very dire. find americans being very dire. and joe biden talking _ americans being very dire. and joe biden talking about how russia has one of the biggest armies in the world. is there a

sense that the present�*s rhetoric is different to european leaders and maybe he is pushing the chance of an invasion than may be more than people like borisjohnson is? we have seen it ebb and flow over the last few days and weeks as to where the most dire predictions have been coming from and sometimes it seems as if it's been the us and other times it seems to have been in europe or the uk and across the board nato countries are speaking with one voice and the evidence is that it's clear that along the border we have exercises in belarus taking place and belarus being a close ally. the message is there for ally. the message is there for all to see and that is what the white house is talking about and it doesn't really need much rhetoric from the president to

speu rhetoric from the president to spell out the seriousness of the situation.— spell out the seriousness of the situation. and the ukraine complaining — the situation. and the ukraine complaining about _ the situation. and the ukraine complaining about russian - the situation. and the ukraine i complaining about russian naval forces going on and blocking the sea and it's obviously a developing situation. that's all we've got time for. thanks forjoining us. britain's most senior police officer, the chief of london's metropolitan force, has resigned. cressida dick is leaving the post two years earlier than expected after the mayor of london expressed reservations about her ability to reform the police force. a recent police watchdog report into misconduct found evidence of racist, anti—semitic and homophobic behaviour. june kelly reports she made history when she became the first female commissioner of the country's largest force. but tonight, cressida dick's long policing career was brought to a sudden end. following contact with the mayor of london today, it is quite clear that he no longer has sufficient confidence in my leadership of the metropolitan police service for me to continue as commissioner. he has left me no choice

but to step aside. the mayor, sadiq khan, had already put out his statement. it's clear that the only way to start to deliver on the scale of the change required is to have new leadership right at the top of the metropolitan police. what would be a decisive day on the job for cressida dick began at the bbc, and a radio phone in. responding to a grilling about her performance, she pledged her determination to carry on. i have absolutely no intention of going. 24 hours earlier, the mayor of london, sadiq khan, had issued an ultimatum. my expectation is the next time i see her i want to see what her response is. but their working relationship is over. the finale to a torrid 12 months from the met.

it was almost a year ago that one of their own officers, wayne couzens, used his police powers to kidnap sarah everard off a london street and then rape and murder her. with a killer policeman under arrest, as women gathered for a vigil in memory of sarah, these were the images which went viral. more bad headlines for the met. the reputation of the met| was much more important than the people she was meant to serve. - by not admitting that there are deep systemic issues, i they are not going to be able to solve them. _ while pressure has been building on cressida dick, a few months ago politicians gave her more time, with priti patel extending her contract. now the behaviour at number 10 has led to the partygate investigation, but even in this, the met has gathered more criticism for being flat—footed in its response. and then, in recent days, shocking messages sent by some officers at charing cross police station lifted the lid on racist and sexist attitudes which were redolent of policing in the 1970s.

in a separate scandal, two officers regarding a murder scene where two sisters had been killed also sent abusive messages. those officers ended up in prison. after five years at the helm, cressida dick will soon be leaving scotland yard for the last time. the murder of sarah everard and many other awful cases recently have, i know, damaged confidence in this fantastic police service. there is much to do, and i know that the met has turned its full attention to rebuilding trust and confidence, and to raising our standards.

tonight, the home secretary paid tribute to dame cressida. she began the job as a popular pioneer, but her tenure has ended with her losing the faith of both the politicians and the public. some breaking news now, and the 15 year old skater at the centre of an olympic doping controversy faces a fight to stay at the winter games in beijing. it's been confirmed that ice skater kamila valieva tested positive for a banned substance before the games started. but her provisional suspension was lifted by the russian anti—doping agency and a decision the ioc will now appeal. valieva was part of the winning team event and is due to compete in the individual figure skating event next tuesday. now to canada, where the chaos caused by the trucker protests is spreading. three us—canada border points have been affected, including

the ambassador bridge, one of the most important trade corridors between the two countries. samira hussain has the latest. for yet another day lorry drivers, furious at maxine van dates and covid restrictions have blocked the busiest border crossing in north america. it just keeps going on and on. crossing in north america. it. just keeps going on and on. the economic impact could be serious. a quarter of all trade between canada and the us happens here or it did until trend is —— truckers intervene. we want freedom. you cannot force — we want freedom. you cannot force things on people. many people — force things on people. many people have lost things with these — people have lost things with these lock is now with the mandates.— these lock is now with the mandates. the protests are forced to — mandates. the protests are forced to have _ mandates. the protests are forced to have the - mandates. the protests are forced to have the worlds . forced to have the worlds largest car—maker is to suspend operations, a financial burden that has caught the attention of the white house. i that has caught the attention of the white house.- of the white house. i think it's important _ of the white house. i think it's important for— of the white house. i think it's important for everyone | of the white house. i think l it's important for everyone in canada and the us is to understand the potential impact of this blockage on workers, on

supply chains and that is where we are most focused. it’s supply chains and that is where we are most focused.— we are most focused. it's a focused — we are most focused. it's a focused or— we are most focused. it's a focused or local _ we are most focused. it's a j focused or local businesses we are most focused. it's a i focused or local businesses in ottawa where the original trucker protest continues to obstruct davey —— daily life and commerce but for the police force attentions turn to the impending confrontation. on wednesday they started warning truckers they would be arrested and forcibly removed if they don't leave their own. the response to the threat could dramatically change the carnival atmosphere which has prevailed, all of which seems strange in a country and political system once renowned for its good manners. both canada's protesters can be removed from the roads and then businesses will likely bounce back and as covert is starting to recede, so do the restrictions but the anger it has revoked —— provoked might not be easily reversed. i've been speaking to stephanie carvin, a former national security analyst,

and now, associate professor at ca nada's carleton university. i asked for her thoughts on the governments handling of the protests. it's mind—bogglingly bad. from the beginning they seem to have misunderstood the nature of this movement, which, of course, has been driven by extremists who turned to extremist tactics and then seem to be stunned and had no response and that municipal level in ottawa they have tried to say there is no policing solution and federal involvement required but at the federal level they have said that this is a police matter and while they will support police and provide additional resources they don't want to get involved. and at least where i live in ontario government has been largely absent in the first major action they took was a few hours ago when they have moved to try and stop or at least freeze the money and some of these large crowdfunding

campaigns we've seen that, honestly, the government seems at a loss to ask and they are suffering as a result. you talk about crowdfunding campaigns but how significant have they been to the movement which seems to be building in many cities? it's not something i'm sure we've seen before in the sense that these crowdfunding sites are a vehicle for movements, and some of the crowdfunding platforms have been associated with funding extremist movements before but in this particular case we seem to not only have the crowdfunding website being used to raise money but it's also become a symbol of resistance, like in energy. i probably wouldn't be on bbc now if this campaign had only raised $50,000 and in this sense it's become what has become the focal point and energy so even in the thick stream list movement and convoy doesn't get their hands on the money, these crowdfunding platform serve extremist ends by giving money and perpetuating the situation in canada. it's notjust canada is seems

to be spreading around the world and in france we here in paris in the next few hours and australia and new zealand. do you see it spreading further or it will fizzle out? it's going to be interesting to see as they were attempts in canada to set up convoys and other city and toronto and quebec city, they knew a convoy delegation, i suppose was coming into their cities and they took appropriate actions and were able to manage it and not allow the vehicles to get entrenched and i have no doubt that the brazilian authorities are used to dealing with large—scale protests so i hope they are prepared in a similar way and can avoid the situation that ottawa is in but if you go on the facebook pages and you watch the live streams there is so much international support for the movement. let's face it. canada is normally not that interesting of a country so i think this movement is bolstered by the perception that there is widespread international support for it and, effectively, they are exporting their model of protest to other countries.

heading back where it belongs — the painting looted by the nazis now being returned to the family of its original owners. there's mr mandela, mr nelson mandela, a free man taking his first steps into a new south africa. iran's spiritual leader, ayatollah khamenei, has said he's passed a death sentence on salman rushdie, the british author of a book which many muslims say is blasphemous. the people of haiti have flocked to church to give thanks for the ousting of their former president, ba by doc duvalier.

because of his considerable value as a stallion, - shergar was kept in a special secure box in the stud - farm's central block. shergar was driven away. in a horse box the thieves had brought with them. there stepped down from the plane a figure in mourning — elizabeth ii, queen of this realm and all her other realms and territories, head of the commonwealth, defender of the faith. britain's most senior police officer is to step down after the mayor of london said he had no confidence in her leadership. president biden has told us citizens to leave ukraine immediately, warning "things could go crazy quickly" in the region.

let's stay with that top story now. ukraine has accused russia of blocking its access to the sea, as the kremlin prepares for naval exercises next week, amid the spiralling tension in the region. six russian warships, equipped for amphibious landings, have arrived in the crimean military port of sevastapol. some have travelled from russia's bases in the baltic to reach the black sea. this map released by the ukrainain navy shows the areas of sea it alleges are being covered by the planned manoeuvres. while not formally a blockade, it could severely limit routes for ukrainian shipping, including cutting the straights of azov between crimea and russia. the naval drills do not occur in isolation. thursday saw the start of 10 days ofjoint military excercises between russia and belarus. and images — collected over the last 48 hours by satellite company maxar technologies — have shown additional military buildup on ukraine's eastern border, stretching to ukraine's south in russian—annexed crimea, as well as near ukraine's northern border with belarus.

earlier i spoke to michael sheldon — open source analyst with the atlantic council's digital forensics lab — about what they'd observed on the belarusian border the scale of the deployment is what is constraining here, the fact that they have pulled so many troops from all across the country, even from the russian far east, nearly half across the world by training to belarus and it's particularly concerning.— belarus and it's particularly concerning. michael, can you talk as for— concerning. michael, can you talk as for your _ concerning. michael, can you talk as for your methodology | talk as for your methodology and as an illustration can we see the sources your sources use from russian tick—tock. taste use from russian tick-tock. we use from russian tick-tock. we use open _ use from russian tick—tock. - use open source those. and we

seek to verify and the process of geolocation and we use the process to narrow down the area and satellite image to cross—reference from the scene to the actual location. you mention — to the actual location. you mention geolocation - to the actual location. you mention geolocation n'jie geo— locate equipment arriving by rail at the corinne vo station. talkers through that.- talkers through that. same process- — talkers through that. same process- we _ talkers through that. same process. we noticed - talkers through that. same process. we noticed a - talkers through that. same | process. we noticed a large amount of equipment, also auxiliary pieces arriving at the station in kursk and we saw them move north—east. and it was and from there on and it

was and from there on and it was up for us to guess from where we went from there. here in the uk, prince charles has tested positive for covid for a second time. it's understood he met the queen just two days ago. a warning, there are flashing images in this report from our royal correspondent, nicholas witchell. the british museum in london last night, a reception for the british asian trust and the guest of honour prince charles and his duchess, the duke of, and everyone was shaking hands freely and amongst the guests that the prince shook hands with was the chancellor, were taken, charles took a routine covid test and it's the second time he's caught it and he is triple vaccinated and thought to be coping well. but two days ago he was presiding at an investiture in windsor castle and while he was there he met the queen. she had just returned

from sandringham where she had been seen in good spirits at the weekend, marking the 70th anniversary of her accession to the throne, so inevitably, a concern. might she have contracted covid during the meeting with the prince of wales? as with all medical and health—related matters, buckingham palace is saying the absolute minimum. all the royal sources will say is that the queen is not displaying any symptoms of covid. it can safely be assumed that the queen has been triple vaccinated, but it's not known whether she has been tested for covid or what any such tests have indicated. all the palace will say is that the situation is being monitored.

the french virologist, luc montagnier, who won the nobel prize for medicine for his co—discovery of the virus that causes aids, has died at the age of 89. stephanie prentice reports. he was the man who helped tackled the fear, damage and death spreading through the 1980s as the aids epidemic unfolded around the world, baffling scientists. the virus can be passed during sexual intercourse with an infected person. luc montagnier isolated human tissue from a neck gland in 1983 and was able to draw the link between a virus in it and aids. he battled to be recognised as the first scientist to reach this conclusion, eventually receiving a nobel prize recognition in 2008 for his work. it is a frequent statement saying that nobel prize winners are less productive after receiving the nobel prize, so i will try not to show this. he went on to develop a specialism in exploring cures for viral diseases but also became a pariah within the medical community for supporting non—scientific theories.

in 2020, this translated to a popularity with modern anti—vaccine movements as he denounced covid vaccines and claimed covid—i9 was made in a lab. despite this, tributes are pouring in with love from his work and with love from emanuel macron for his contribution to the fight against aids. belgium's leading art museum has returned a painting that it's held for more than 70 years — after it was looted by the nazis. the work belonged to a jewish couple who fled their home in frankfurt in 1938. throughout europe there are still many works of art that have yet to be returned

to the descendants of their original owners. the bbc�*s tim allman reports. in a mountain cave, herman i goering's secret treasure trove was located by american soldiers. nobody knows how much art was looted by the nazis. thousands, perhaps tens of thousands of paintings and sculptures. in a mountain cave, herman i goering's secret treasure trove was located by american soldiers. but decades later, at least one work of art is going back to where it belongs. flowers by the german artist lovis corinth was the province of erin meyer when they left behind before they fled to belgium then britain before the war began. but returning it to the descendants was not an easy task. it's not easy. the family doesn't have an image of the painting and i assume they know it comes from the meier family, so both parties have to come together to make a connection. this entire exhibition is of works likely to have been stolen by the nazis and many museums and galleries have been criticised for not doing enough

to return them stop. these works all have different stories but we have put them together because they are all linked to the war. and they all pose a problem of provenance in some way, and it was important to highlight the problem. this is not a simple exercise. no, but the family of gustaf and emma meyer believe it is vital nonetheless. an australian icon — the koala — has been classified as endangered. the number of koalas has fallen sharply along much of the east coast, due to land clearing, bush fires and disease. scientists say the population in the state of new south wales has decreased by up to 60 percent in the past 11 years.

hello again. this time yesterday we were looking at some hill snow in scotland causing a few issues on some of the higher scottish roots and some strong winds gusting at 70 mph in the western isles but a cover of show left over the hills and this was courtesy of this area of cloud, the low pressure currently working across the north sea to bring some fairly windy weather to the netherlands through friday. in the atlantic, we have the next weather system waiting to come into the start of the weekend but between that and that, we get that, an area of high pressure that will be bringing some fine weather our way for friday. however, over recent hours, as the high pressure has edged in, the number of showers has dwindled and a few left in north—western areas and with the combination of clear skies and light winds allowing

a widespread frost, there could be a few icy patches around and the lowest temperatures in aberdeenshire getting down to 10 celsius and a freezing cold start to the day on friday but beautiful winter sunshine for most of you through most of the day, and some isolated showers across the north west and through the day you will see the weather turn cloudy in northern ireland. temperatures? we are looking at highs close to the seasonal average, about six in glasgow and nine for cardiff and london. there will be rain developing on friday night and into saturday the rain will affect parts of england and wales but doesn't reach the south—east of england and east anglia, where it will stay bright and breezy but there will be strong winds for many of us and for scotland and northern ireland, frequent showers and some bright spells between the showers. temperatures a little bit higher, between eight and 10 degrees making it a mild day but perhaps not feeling so given the strength of the winds. talking of winds, the next area of low pressure on sunday looks also set

to bring more wet and windy weather our way. the rain might end up further northwards but not reaching northern scotland where there will be showers around but otherwise the rain will be heavy and it will be a windy day with gales across southern parts of england and wales and through the english channel gusts of around 50 or 60 miles an hour, strong enough to bring down a few tree branches and there might be localised disruption on sunday from the system. next week looks unsettled, often wet and windy, but it does turn very mild for a time. that is your weather.

this is bbc news, the headlines: president biden's told us citizens to leave ukraine now. fears remain that the country's to be invaded by russia as a military buildup near the border continues. the president warned the army's one of the biggest in the world and "things could go crazy quickly". the uk's most senior police officer has handed in her resignation. cressida dick, the head of london's metropolitan police force said she'd been left with no choice after the capital's mayor made it clear he had no confidence in her leadership. in canada, protests led by truckers over coronavirus restrictions are growing. there are blocks and delays on at least three land border crossings into the us, including one of the most important trade routes over the ambassador bridge. car makers report the disruption's having an impact on production. now on bbc news, it's time for hardtalk with stephen sackur.