releasing millions of tonnes of mining waste that engulfed nearby buildings. more than 100 people are now known to have died in the disaster, which happened in the state of minas gerais last month. russia has called america's decision to suspend its participation in a key cold war—era disarmament agreement an abrogation of its international commitments. a russian official said washington had provided no evidence of its claim that russia had for years failed to comply with the intermediate—range nuclear forces treaty. venezuela's opposition leader, juan guaido, is calling for the biggest mass protests in the nation's history this weekend, as he tries to force president nicolas maduro from power. the opposition are demanding new elections to end the political and economic chaos that has been engulfing the country. police are appealing for information about the mother of a baby girl who was left in a park in east london last night. the newborn is now in a stable

condition in hospital. she was discovered by a dog walker in near—freezing temperatures, inside a shopping bag. detectives say her mother may need medical attention and have urged her to come forward. tsb has blamed last year's it problems for a pre—tax loss of more than a £105 million. the bank says 2018 was its most challenging year. about 80,000 customers switched their bank account away from tsb in 2018, 30,000 more than 2017, after some people went weeks without working services. the bank also had to bear the cost of customer compensation and fraud. universities will be required to publish information on what they are doing to tackle the attainment gap between students from different ethnic backgrounds, the government has announced. official figures show that record numbers of ethnic minorities are attending university, but only 56% of black students achieve top grades, compared with 80% of their white peers. as part of a string of measures announced today, universities will be required to publish data on admissions and attainment broken down by ethnicity, gender

and socio—economic background. newswatch is coming up in15 minutes. but first on bbc news, it's time for click. the construction of a wall at the us—mexican border has dominated american politics since donald trump joined

the presidential race back in 2015. we are going to build a great border wall to stop illegal immigration. it reached its crescendo in december, when the now—president announced a federal government shutdown over its funding. we're going to have a shutdown. there's nothing we can do about that. a record 35 days later it was finally lifted, without any real resolution, and it could easily be back on within weeks. as trump tweeted out a new design for his wall, now made of steel rather than concrete, the democrats did offer a potential compromise — to fund a border which used technology rather than physical barriers. but is that feasible, and what would it look like? we sent nick kwek to arizona to investigate. so i'm on my way to the nogales border patrol station,

one of the most technologically advanced control centres on the us—mexico border. the checkpoint itself processes hundreds of thousands of people every month. but today, i'm going on a ride—along with agent dan hernandez of border patrol, whose job it is to keep out those attempting to cross illegally. hey, just be advised i'm going to be around your location. we have 262 linear miles of border fence with mexico, but thousands of miles on the north end on the american side. it's a daunting task, and it's very vast, but with the technology, we're able to get a leg up on our adversaries. dan's patrol zone is larger than the state of newjersey. his sector of duty, tucson, made almost 40,000 arrests in 2017. out in this unforgiving terrain, field agents like him go

about their daily patrol. every piece of technology used by them is vital, and has to be reliable, even down to their radio coms. this one has to have an encryption that's even stronger than most police departments, because of the national security concerns, because of the criminal element. you have a radio that is equipped with gps. so if something should happen, i become incapacitated, i could press that button and help will come. help will come from here, the nogales control centre, where officers can literally see what is going on, thanks to a newly updated surveillance system. their solar—powered integrated fixed towers, also known as ifts, have long—range video and thermal imaging cameras, coupled with radar, to provide high—altitude

points of view, with watchful eyes back at base. we have tracking systems that can detect movement, and it places the camera at the source of the movement. before, we'd see some pixelation from the cameras, just by the remote nature of their placement. it was very difficult to focus far away. but with technology, we've increased the amount of distances we can see and the accuracy of the images, and we're seeing really crisp, sharp images. so we're able to identify things that come over the fence, people that come over the fence, contraband that comes over the fence, and not only that, but it increases safety. if i go out to an area and i don't know what i'm waiting on, and i don't know what's out there, and i run into an assailant with a firearm, it might be a bad situation. but if i know that, prior to going in there, i might be able to bring other resources with me. as well as saving agents‘ time, and potentially saving them, the ifts have helped secure areas where physical barriers are not. down here, fencing has been raised to prevent erosion from water flow,

but a person could easily walk through here. for all intents and purposes, we consider this defence the wall. so we don't want to think this is the only thing keeping america safe. we have the fencing as a tool, as another system we can utilise, but it by no means is supposed to keep anybody in or out. we are the force, with the agents, in conjunction with the technology, and this being utilised as a tool, that seamless integration of all three components is what makes the border secure, is having the agents to make an arrest, the wall, and then the technology to supplement it. this could be just a couple of miles, or it could be a couple of hundred yards. five minutes down the road, dan shows me a border section where technology is already having to do most of the work in keeping people out. just looking at this, this is completely not what i was expecting to see, i guess, when people have visions of the wall or, you know, the mexican border,

the us—mexico border. like i said, the presence of the fence isn't here. it's not a very powerful fence, by any means. it's just meant to keep vehicles out. whilst these sticks won't stop determined individuals, i'm told scattered sensors buried in the ground all around the area could catch them offguard. technology is intended to help agents do their duties. but, of course, it is not always criminals that get caught in the net. the recent migrant caravan crisis highlighted how many families make the perilousjourney in hope for a better life in the us. many have been torn apart, and some children have died since being detained by authorities. for dan, he says he is just doing hisjob. no matter on what side of the spectrum you fall on, border security is important for the entire country. we're law enforcement officers. we don't dictate the law, we just enforce the laws, so the best way to enforce the laws is by doing it in the most effective and most efficient way.

as well as giving agents eyes—on from a long range of rural terrain, imposing structures have also been used to mitigate crime in urban areas. so up that hill there is a rvss tower, or remote video surveillance system, which is keeping a close eye across this area, which historically has been quite dangerous. but having that eye in the sky has helped improve safety — or so i thought. on top of that tin roof there. yes, those are rocks. yes, those are all rocks thrown at agents. 0k, we got to get out of here. yeah, you got to go, you got to go, you got to go. so actually — we actuallyjust heard a rock land on the top of that garage there, so obviously people up there are throwing stones at us. so we're heading out. no—one is hurt, just be advised it's for safety.

this is an area where usually scouts or people involved in human smuggling are perched, and i believe there's one person underneath that tree. so he's a human smuggler scout. while scouts may sit for hours at a time, people crossing the desert move from place to place, so border patrol have mobile surveillance trucks to reach remote areas. they're equipped with thermal rangefinders, enabling operators to measure the distance between themselves and people crossing, and laser pointers, to give agents in the field wearing nightvision goggles a heads—up. customs and border protection has also begun testing drones with facial recognition cameras to help monitor the border from an even higher vantage point, and border patrol is trialling a new mobile—based navigation tool so agents can keep track of each other‘s live whereabouts. the border is changing every single day, and technology or investment in technology allows us

to keep up with the trends, with the smugglers, with counteracting any kind of negative action towards the united states at the border. whilst trump's wall continues to be a bone of contention, maintaining the border stretches beyond simply erecting more steel fencing. as i have come to learn, communication tools and surveillance systems play a pivotal role in everyday operations. whether technology can replace a wall altogether here is something which will be debated in the coming weeks. in time, you will know what it's like to lose, to feel so desperately that you're right, yet to fail all the same. i think it's 3,500 vfx shots, which is a huge number for a film. hear me, and rejoice. it was a major sequence, so it's the part of the film where ebony moore comes down to try

and get the time stamp from dr strange. because we were on the show fairly early, in the preproduction phase, all of the designs of the suits were still really only in sort of 2—dimensional form. concept artists from marvel had worked those up, and part of our brief was to try to realise them in cg, and realise them in terms of motion, how they actually would move and work. so iron man's suit was a big part of that, its nano—tech. robert downeyjr had quite a bit of input into how that worked. so it has a couple of cords that you pull and the sujit tightens and allows the nano—tech to kind of spread out over it, which was his idea. spider—man has got his own problems as a character,

because he's so bendy, and i think quite often, the dislocations in his anatomy that would occur if you got into that kind of position are quite often hidden artfully in lighting. a lot of the effects are defined by the story and the storyboard. down to what happened to bricks, and making little darts out of bricks, that fly. we always look for reference, and he is an alien, so it's hard to find a reference. the character is old in quite distinguished, he is a wizard, so we looked a distinguished looking english actors, like peter cushing and christopher lee, took cues off their hair, what does their skin look like? and try and infuse some of that character and posturing into the character. you exhaust me.

bring me the stone. and that's it for the short cut of click this week. full version is waiting at iplayer, as are we on social facebook, instagram, and twitter, where we live at bbc click. thank you, and we will see you so on. hello and welcome to newswatch with me, samir ahmed. brexit is getting closer — how well is bbc news managing to explain the process of leaving the eu 7 and chops away, just how did the bbc managed to suggest that bbc could —— theresa may could be flying off to brussels in the bbc‘s spitfire. it has been another week of brexit

drama and with fewer than 60 days until the uk's scheduled departure from the eu, the arguments have been rating ever more passionately. he is the conservative mp, mark francois, vice—chairman of the pro—brexit european research group, responding to the german chief executive of airbus who suggested the company might have to leave the uk in the event of a no—go brexit. if he thinks because he runs a big company he can bully british mps out to vote, he will be sorely mistaken. my father was a d—day veteran and he never submitted to bullying by any german and neither with his son. if mr enders is watching, that is what he can do with his letter.