a very warm welcome to bbc news, broadcasting to our viewers in north america and around the globe. my name's mike embley. our top stories: a diplomatic rift over the border wall. president trump suggests taxing imports from mexico. president pena nieto cancels next week's trip to washington. u nless unless mexico is going to treat the united states early, with respect, such a meeting would be fruitless. britain's prime minister will meet mr trump on friday to talk trade. celebrations in the gambia for the first peaceful transfer of power in the country's modern history. and it may not look much, but this rough diamond is the largest uncut stone ever found in north america. we can give you a special close—up look. if mexicans hoped donald trump's promises on the campaign trail

were just bluster and bravado, it looks as though they, and many americans who voted against him, are in for more disappointment. mr trump has already ordered a start on the border wall, and now the white house is threatening a new tax on mexican imports. mexico's president has cancelled a visit to washington next week, a meeting mr trump said would be fruitless. so, if the two countries are heading for a possible trade war, how much money is involved? official figures for 2015 show the united states exported nearly $270 billion of goods and services to mexico. in the same year, mexico exported more than $316 billion of goods and services. so, the us had a trade deficit of nearly $50 billion dollars. the white house says for 2016, that figure was $60 billion. nick bryant reports. donald trump's new executive toy. his first ride today on air force one, that potent symbol of us presidential power.

but it was the cancelled travel plans of the mexican president that were at the centre of a diplomatic storm. his plane will stay grounded after a summit between the two leaders scheduled for washington next week was abruptly called off. this mexican stand—off is over the great totem of the trump presidency, the wall he's determined, notjust to build along the border, but also to get mexico to pay for. but in an angry speech last night, the country's president, enrique pena nieto, said he wouldn't foot the bill. so, shortly before leaving the oval office this morning, donald trump decided to conduct his diplomacy by tweet. "if mexico is unwilling to pay for the badly needed wall, then it would be better to cancel the upcoming meeting." by the time he spoke in philadelphia, the mexicans had announced the summit was off, and that earned a public scolding from president trump. the president of mexico and myself have agreed to cancel our planned

meeting scheduled for next week. unless mexico is going to treat the united states fairly, with respect, such a meeting would be fruitless, and i want to go a different route. almost a week into his term in office, it's already becoming clear that donald trump is changing the presidency more than the presidency is changing him. 0n prime—time tv last night, the former property tycoon gave a tour of the country's most prized piece of real estate and it was vintage donald trump. i don't want to change too much. i can be the most presidential person ever, other than possibly the great abe lincoln, all right? but i can be the most presidential person. he's still obsessed with the crowd size at his inauguration. a sea of love. but in a new interview with fox news, he turned his attention to the group calling itself "islamic state," saying its fighters were sick and demented.

the people that we're going against, they don't wear uniforms, they're sneaky, dirty rats. and they blow people up in a shopping centre. and they blow people up in a church. these are bad people. the presidency is travelling at a hurtling pace. the late—breaking news tonight, that he's now calling for a 20% tax on mexican imports to pay for the wall. donald trump is clearly revelling in his seat of power, whether it's in the oval office or at 30,000 feet. beautiful. great plane. nick bryant, bbc news, washington. britain's prime minister theresa may has arrived in the us to start a trip she hopes will pave the way for a post—brexit trade deal. she'll be the first foreign leader to hold talks with donald trump at the white house. 0ur political editor, laura kuenssberg, is travelling with mrs may. 0pposites attract. theresa may's hope. but how close does she want to get to him? the prime minister made a quieter

arrival, making her way down the windy steps in philadelphia. her convoy speeding towards her debut in trump land, here to make friends. no hate, no fear. a reminder right outside the 5—star hotel where they were both to speak, donald trump has many enemies as well. the prime minister's warm up act was the president himself. is he ready for her? i'm meeting with the prime minister tomorrow, as you know. great britain. i'm meeting with her tomorrow. i don't have my secretary, they want to talk trade, so i'll have to handle it myself. laughter. which is ok. then it was her turn, with, as you would expect, fulsome reference to the friendship across the atlantic. it has been america's destiny to bear the leadership of the free world and to carry that heavy

responsibility on its shoulders, but my country, the united kingdom of great britain and northern ireland, has been proud to share that burden and to walk alongside you at every stage. applause cheering but this is much more than a meet and greet. theresa may came with a serious message for republicans and the world. under her leadership, no more western conflicts like iraq, or afghanistan, she suggested. this cannot mean a return to the failed policies of the past. the days of britain and america intervening in sovereign countries in an attempt to remake the world in our own image are over, but nor can we afford to stand idly by, when the threat is real and when it is in our own interests to intervene. we must be strong, smart and hard—headed, and we must demonstrate the resolve necessary to stand up for our interests. and a warning perhaps directed

at the president over an assertive russia. when it comes to russia, as so often it is wise to turn to the example of president reagan, who, during his negotiations with his opposite number mikhail gorbachev, used to abide by the adage — trust, but verify. with... applause with president putin, my advice is to engage, but beware. noticeable as well, her praise for the republicans and president trump's controversial win. because of what you have done together, because of that great victory you have won, america can be stronger, greater and more confident in the years ahead. even before she touched down though, theresa may had a taste of how much political trouble closeness to president trump could cause.

number ten believes the risk is worth it, because there's a big opportunity as well, but this new friendship could cause fireworks every time donald trump's speaks his mind. like suggesting torture, banned under british and international law, works. i want to do everything within the bounds of what you're allowed to do legally, but do i feel it works? absolutely i feel it works. the prime minister was adamant britain won't change its laws and signalled we might stop sharing intelligence with america if torture was brought back. here among the republican top brass, the idea is unlikely to fly. the deep—seated policy in american culture is not to torture. so theresa may is right and president trump is wrong? i didn't say that. just one of many awkward subjects the pm and president could discuss tomorrow, a test, even in politics true friends tell the truth to one another, not merely platitudes, or what they want to hear.

laura kuenssberg, bbc news, philadelphia. president trump's chief strategist, steve bannon, has described the mainstream media as the opposition party, and said it should keep its mouth shut and listen for a while. in an interview with the new york times, mr bannon said news organisations should be embarrassed and humiliated by their failure to anticipate mr trump's election victory. the new president of the gambia, adama barrow, has flown back into the country. mr barrow was inaugurated last week in senegal for his own safety while regional leaders persuaded his predecessor, yahya jammeh, to step down. he is now in exile in equatorial guinea. alistair leithead reports from the gambia. a long—awaited return for the gambia's new president. it is the first time power here has peacefully passed from one leader to another.

adama barrow was inaugurated in senegal, when the man he defeated at the ballot box refused to leave. expectations are high. the former dictator, yahya jammeh, went into exile last weekend after weeks of pressure from neighbouring presidents. a rare case of african leaders strongly policing democracy. the threat of military action from a regionalforce helped. they now provide security for the new president, still unsure where his army's loyalty lies. now he will need fancy footwork to deliver on all the political promises. it is a poor country. young talent often leaves. this is the gambia's top women's team. their goalkeeper drowned last year trying to cross the mediterranean. she was 20 years old. her brother thinks she may have hoped to play in europe

and so joined a well—trodden path. thousands of people go. why? what we believe is that we want to be out and do something for ourfamily or something like that. who knows, to be honest? in villages all across the gambia, many, many people are taking what they call here the back way to europe. starting here they cross throug senegal, through mali, through burkina faso to niger, where they head north through the sahara desert to libya and from there they try to cross the mediterranean into europe. fancy new houses built in poor villages show what reaching europe means. money sent home makes a huge difference here. it is a big incentive. this man is 26. he tried and failed. the family supported his plan to migrate and were disappointed

when he came home after a terrible experience. it was so hard. kidnapped by criminals, he was imprisoned for one month and then stranded with no money in southern libya he asked the un help him get home. there is hope here that a new president can revive the economy and remove the need for young people to leave. but it will not happen overnight. in other news: the philippines has reversed its stance on american bases, announcing the united states will now upgrade and advance its facilities on bases in the country. last year, president duterte said he wanted us troops to leave and called for an end to alljoint military exercises in favour of building closer ties with china.

authorities in austria have detained 11 men and three women they suspect of belonging to the extremist group that calls itself islamic state. around 800 officers carried out raids in vienna and the southern city of graz. the suspects include three austrians described as having a migrant background as well as a syrian and men and women from the balkans. the russian government is sending a super tanker aircraft to chile to help the country fight the worst wildfire in the country's modern history. the series of fast—spreading fires mostly in chile's central region, are being fanned by strong winds, high temperatures and a prolonged drought. 0ne town, santa 0lga, has been completely destroyed by the flames. stay with us on bbc news. still to come: we're 30 seconds closer to armageddon. since president trump's inauguration, peace activists have moved the doomsday clock nearer to midnight. the shuttle challenger exploded soon after liftoff. there were seven astronauts on board, one of them a woman school teacher. all of them are believed

to have been killed. by the evening, tahrir square, the heart of official cairo, was in the hands of the demonstrators. they were using the word "revolution". the earthquake singled out buildings, and brought them down in seconds. tonight, the search for any survivors has an increasing desperation about it as the hours pass. the new government is firmly in control of the entire republic of uganda. moscow got its first taste of western fast food as mcdonald's opened their biggest restaurant in pushkin square. but the hundreds of muscovites who queued up today won't find it cheap, with a big mac costing half the day's wages for the average russian. this is bbc news. the latest headlines: the white house has said

president trump may tax imports from mexico to pay for his border wall. the mexican government has warned that will hurt american consumers. the british prime minister has told an audience of senior republican politicians she is looking forward to talks about a new free trade deal between britain and the us. more now on day six of america's new president, and the war of words between mexico and the us over the proposed wall along the border. one of the most vocal critics of the wall is mexico's former president vicente fox. hejoins us now from mexico. very grateful for you giving very gratefulfor you giving us very grateful for you giving us your time. you have made your views very clear on social media, all your tweets about the wall come with a swea ry tweets about the wall come with a sweary hashtag we cannot repeat here. mexico paying for the wall is simply not negotiable. where is this dispute heading our? how will it be resolved? well, it will go as far as

mrtrump wants. if resolved? well, it will go as far as mr trump wants. if he keeps pressing mexico, if he keeps discriminating mexico, if he keeps discriminating mexico, against other countries that have larger deficits than mexico, we will go as far as needed. 0ur president has declared now that if needed we would withdraw from nafta, and leave the united states alone, losing 10 million usjobs that mexico provides for them, throughout imports. so they have everything to lose and nothing to win. i hope the united states citizens wake up. i hope congress of united states open their eyes and see that this guy is taking the united states economy to the drain. the us could get money out of mexico, couldn't it, a border tax or by tapping remittances that

mexicans send home or as a repayment for renegotiating nafta. for mexico to pull out of nafta would be devastating for the country, wouldn't it? that is not true, that is not true. let me tell you quickly. number one about the tax, the 20% tax. if he taxes imports to the 20% tax. if he taxes imports to the united dates, products for consumers in the united states will increase 20%, the price. so who is paying for the wall? us citizens. second, this is a mirror effect. if he taxes 20%, the 250 million us dollars a week export to the united states immediately, that same day, and this has been already made public, mexico would tax 20% —— that we export. all us exports to mexico, which amount to 250 million us dollars. so there is no winning for

nobody, everybody will lose. this trade war is stupid, but this is his own initiative. he is absolutely wrong that he is protecting usjobs through the measures he is taking. 0n the contrary, he would be losing jobs to us citizens by breaking with nafta. you have been a president yourself, of course. what do you say to president trump's law and order point that undocumented immigrants are involved in various elements of criminality and he is a responsibility to do something about that? i expect that part of undocumented immigration, just like you have in britain, from africa, where else, that has to be agreed. mexico is working hard to solve that. either way, now mexico is working hard to solve that. eitherway, now people mexico is working hard to solve that. either way, now people leaving mexico to the united states is one third of what it used to be. so

mexico is solving the problem. now, about criminality, that is a lie. it is stupid. he has never proven that mexico is particularly criminals. i see much more death tolls, many more crimes committed, by us citizens. because they can have a gun at any time they want, and it is not mexicans. now, ifany time they want, and it is not mexicans. now, if any mexican commits a crime in the united states, he should be caught, put in jailand states, he should be caught, put in jail and sentenced to a long—term in prison. that, we accept. that is not a problem. but now he is saying that he will give a ticket and send them back to their country of origin. that is wrong, that is notjustice. he should catch him, put him in jail, take him to court and come up with a penalty for them. that is accepted. if he wants to build a wall, let him do, if he wants to throw 25 billion us dollars to the

basket, instead of using those $25 billion to invest in schools, invest in infrastructure, let him do. we're not saying don't old wall. we are saying we are not paying for a wall that you have decided, stupidly, to build —— don't build a wall. and thatis build —— don't build a wall. and that is none of our business. very good to talk to you, thank you very much. a pleasure, sir. for the past 70 years, the bulletin of atomic scientists has been setting the metaphorical time on what it calls the doomsday clock. it is their way of measuring, in the age of atomic weapons, how close they feel the world is to total destruction. on thursday, the group announced it was moving the hands 30 seconds closer to midnight, the symbolic moment when it suggests the earth would face apocalypse. the reason? the pronouncements of president trump. here is rachel bronson, speaking for the group, to explain. perhaps most troubling has been two concerns that are adding to an already challenging global landscape. the first — the first has been the cavalier and reckless language

used across the globe, especially in the united states during the presidential election and after, around nuclear weapons and nuclear threats. and the second is a growing disregard of scientific expertise, expertise that is needed when it comes to responding to pressing global challenges, including climate change. a study of 400 american schoolchildren suggests girls start to see themselves as less innately talented than boys when they are only six years old. researchers read a story about a really intelligent person to young children. they found that both boys and girls, from the age of six, tended to think of the smart character as male. the scientists describe the results as disheartening, because the impact may snowball to affect future careers. the foxfire diamond is the largest everfound in north america, and it has been on display at the smithsonian's natural history museum in washington. jane 0'brien went along to marvel. this story of the foxfire diamond began 2 billion years ago

when it was forged by fire and forces deep beneath the earth. now, the largest uncut diamond from north america is being studied by scientists at the national museum of natural history. it looks like a lump of quartz. and you know, i think a lot of people would agree with you. in fact, i'm sure a lot of people, if they saw that just laying on the side of the road, would probably not even think about picking it up. diamonds are as mysterious at meteorites. both travel through time and space, to offer clues about the origins of the universe. this diamond's perilous journey is even more remarkable, as most are destroyed or splintered by the volcanic action that propels them at high speed to the earth's surface. we know by looking at these flat surfaces that there was more to this diamond at one time. that during either this violent ascent, as part of this vulcanic eruption,

or the explosion at the surface, or the mining operation, something caused this diamond to be broken. and these flat faces are the broken cleavage surfaces. so someplace, someplace, there are other pieces to this diamond. we better get hunting. we better get lucky. we do not know if this is the biggest or the smallest piece. but somewhere there are other pieces that would fit onto these flat surfaces right here. on friday evening, millions of families in china and across the world will gather for reunion dinners celebrating the lunar new year. often people travel thousands of miles, and it will be the only time this year they get to spend time with their relatives. but there are some who choose not to go home. we have been to meet one. a reminder of our top story: the white house has said president trump may impose a 20% tax on imports from mexico to help pay for his proposed border wall, he says to

keep out illegal immigrants and drugs. mexico's foreign minister has said that the wall is simply not negotiable, and former president fox has told this programme it is a stupid idea, which won't work. and you can get in touch with me and most of the team on twitter. hello. well, while some of us were shivering on thursday, for others, for example across the north of scotland, it was remarkably mild. a day of contrasts. we are kind of getting back to normal through this weekend. most of us will turn less cold. a bit of a breeze, some sunshine, but there will be some rain around, too. we are losing the continental feed which brought most of us a very cold day on thursday. we are doing to start to drag air in off the atlantic, and hence that rise in temperatures for the majority. but we start the day with a hard frost, one or two freezing fog

patches, and the odd shower as well, which could cause some icy stretches. it should be a dry start across wales, that fog up over high ground, but that will be lifting, and the temperatures will be on the rise, above freezing for northern ireland. rain knocking on the door of the west of the province. a frosty start for most of scotland. and here i think it is set to be a largely dry day, with some sunshine. heading our way down, across the borders into northern england, cold with a hard frost, some freezing fog patches for sure in the morning, so watch out for those. i mentioned the odd showerjust spilling into eastern counties for a time in the morning, so the risk of one or two icy stretches. but temperatures slowly rising above freezing. down across southern england and into the south—west, we should be above zero. a dry start, but some showery rain lies in wait out west. and this band of showery rain will start to push its way slowly eastwards, across northern ireland and into the far south—west of england, perhaps the far south—west of wales. another little area of showers pushes up across southern england through the afternoon as well.

further north and east, it stays dry, but that chilly air holding on for one more day. just two degrees there in newcastle. milder, though, across many southern and western areas. as we head through the evening and night, it gets a bit messy. there will be areas of rain pushing their way northwards and eatwards. some of that quite heavy, actually, some quite wet weather, and a period of snow up over the higher ground of scotland, in particular. but something a little bit clearer will folllow on behind. temperatures could dip late, close to freezing. but for most of us, actually, it will be a frost—free start to the weekend. saturday starts with cloud and some patchy rain, continuing to move northwards and eastwards. behind that, it turns brighter, but also with some showers. and one or two of those showers could be wintry up over the high ground. but it will not be anything like as cold as it has been for most of us. double figures in a few southern areas. that milder theme continues into sunday. we could see an area of rain pushing into southern areas. how far north that gets

is open to question. best of the brightness on sunday will be further north across the uk. milder than recently. i'm mike embley. the latest headlines from bbc news: the white house has said president trump may impose a tax of up to 20% on imports from mexico to help pay for his planned border wall to keep out illegal immigrants and drugs. the mexican economy minister has said the idea won't work because it willjust put up costs for american consumers. the british prime minister, theresa may, has said britain and the us should not return to what she called the failed interventionist policies of the past. mrs may was speaking to republicans in philadelphia at the start of a visit that will see her become the first foreign leader to meet president trump. the gambia's new president, adama barrow, has returned home to scenes ofjubilation. thousands lined the streets as his convoy travelled to the capital. mr barrow was inaugurated last week in senegal for his own safety while regional leaders persuaded his predecessor, yahya jammeh, to step down. now on bbc news: hardtalk.