this is bbc news. the headlines: theresa may and jeremy corbyn have been facing questions from voters in the final televised debate before next week's general election. mrs may stressed that she was the best person to lead brexit negotiations and mr corbyn promised a left—wing alternative to the government's planned spending cuts. the white house has defended donald trump's decision to pull the us out of the paris climate agreement. administration officials say it's now up to other world leaders to decide whether to sit down and negotiate a new deal. however, china, india and the eu have recommitted to the original agreement. the new leader of the biggest party in ireland's coalition government, fine gael, is leo varadkar — the son of an indian immigrant who is ireland's first openly gay minister. aged 38, he is set to become ireland's youngest prime minister in a few weeks‘ time. coming up shortly on bbc news, we

will have new swatch but first it is time for click. —— news watch. summer is on the way and, well, it wouldn't be a british summer without a visit to a good old fashioned festival. no, not that one. much better. known as the town of books, hay—on—wye, in wales, is the location of the hay festival. it's a literary mecca, an annual gathering of artists, authors, daleks and, yep, even royals. it's even been called the woodstock

of the mind by none other than former us president bill clinton. this year it's the 30th hay festival and the line—up is pretty stellar. well, for the second year in a row, we've been invited to share some of our favourite experiences and show off some really good tech, all in front of a real, live audience of actual people. what could possibly go wrong? a packed tent waited, all that we had to do was wow them! applause. we have robots falling over, experiments in haptic feedback and demos in binaural sound, but that was nothing compared to the climax — a click—created wavy, shouty game built using artificial intelligence. in the meantime, it can't have have escaped your attention that around the uk things are getting a touch political. as the general election looms, those

politicians are using increasingly sophisticated techniques in order to learn more about us. the advertising reach of facebook has long been an open secret, but now it's something the political parties are getting in on too. in fact, both the trump campaign and the leave.eu groups credited facebook as being a vital part of their electioneering. we know that the personal details that you give to social networks allow them to send you relevant, targeted content, and it goes much deeper thanjust your basic demographics. there are now data analytics companies claiming to be able to micro—target and micro—tweak messages for individual readers, playing to their biases and fears. if you know the personality of the people you're targeting, you can nuance your messaging to resonate more effectively with those key audience groups. what's also emerging is that

political parties have been using this data to reach potential voters, on a very granular level. so who is being targeted on facebook and how? well, until now, there's been nothing around to analyse any of this, but the snap general election galvanised louis knight—webb and sam jeffers to develop who targets me, a plug—in to tell each of us how we're being targeted. when you install the plug—in for the first time, it asks for your age, your gender and your location, and then it starts scouring your facebook feed looking for adverts with a political message. so once you've installed the plug—in, it works in the background to extract the whole advert that you see on your newsfeed. so it pulls out the headline, the subtitle, any related videos, any images, any links. we also get the reaction — so how many likes, how many comments, how many shares — so we can see which messages are getting the most traction. are they particularly

clandestine messages, are they slightly subversive, are they even fake news? but how do data companies get the information in the first place? a lot of the quizzes you fill out on facebook or, you know, you open a survey, it asks your facebook profile to connect to it. sometimes you'll notice that there's a lot of permissions attached and as soon as you click yes, all of your data is mined, and it's then sold on to data brokers who then, eventually, sell it to the political parties for use in their campaigns. although facebook says it doesn't sell our information on, data brokers can overlay any details they mine from the site with other datasets that they have on people based on their email addresses. the next step after that of course is to find similar users that are using facebook and then target adverts, from that advertiser that supplied the email addresses, to those users. why did you choose facebook? it was a really wide demographic. there are just some people that you don't find on twitter. the very nature of the fact that i can't see your adverts,

you can't see my adverts, means that this approach had to be applied to facebook. it's where the problem was. it's a first of its kind anywhere in the world on this scale, giving us citizens some transparency into what we're being shown, but how much can it really tell us? do you think that people wouldn't know that certain things are advert if they weren't using your software? a lot of the time people are scrolling through facebook and the adverts fit into this weird intersection of friend endorsement and advertising. it's quite easy to miss the adverts on facebook. so far, who targets me has some 6,700 users in 620 constituencies, and it's rising as we near polling day. on the down side, it's only as good as the data it's managed to crowd—source, so it isn't necessarily representative, and it also doesn't work with mobile facebook, but the results are interesting.

so we're seeing a mixture of two things. we're seeing, firstly, a/b testing, which is where i try out two different messages with the same group. i see which one gets the best reaction and then i pursue that message. we're also seeing targeting, which is where i pick a particular demographic of people, and then i send a message that's tailored to them. so, for example, it might be young people targeted with register to vote. the data from who targets me is also being poured over by analysts at the london school of economics. one aspect of their research is collecting dark posts, ads which are here one day and gone the next. it gives us the ability to create a respository of those dark posts. so if promises are being made on facebook, in ads which will disappear the day after you use them, we should be able to go back to those after the election, look at them, evaluate them and maybe discuss them in the cold light of day. and the irony is that, as we demand more transparency from public bodies, the whole basis

of political propaganda could be on the brink of a revolutionary change. what's interesting, i think, about the new environment is the potentialfor using paid advertising and other techniques to create individual propaganda bubbles around individual voters. and that's not about controlling the market as a whole, but it's about using smart targeted which, in a sense, creates such a compelling and overarching information environment for individual people that that in some ways constrains what they do and controls what they do. i think that's why some academic commentators and others are beginning to think some of this is a bit spooky. but politicians aren't the only ones with facebook on their minds. the social network was one of many topics on the very large brain of national treasure and tech geek stephen fry. i met up with him after he gave a lecture at the hay festival

highlighting how he thinks the world is being changed by social media, ai and automation. the very current conversation is whether facebook and platforms like them should actually be considered publishers? should they take responsibility for what ends up on the site? they are aware there is a problem, a serious problem. if 80%, some people have said, is the... you know, in proportion of people who get their news from facebook rather than from mainstream media, then surely it is incumbent upon someone who is providing 80% of their news sources to make sure that those news sources are not defamatory, blatant lies, propaganda, the wrong kind of, you know, insulting... i would posit there that a publisher is responsible for all the people that generate the content. yeah. they are employed by that publisher and facebook is clearly not that. yeah. so do we need a third definition, a third thing? exactly. i think there is a median sort

of definition that it's not beyond the wit of lawyers of the right kind to find that. your presentation was a warning that people should prepare for the changes that are coming, for example, artificial intelligence and automation. i said that it was a sort of transformation of the workplace rather than... you know, it's an obsolescence of certain types ofjob, but that doesn't mean forced redundancy of millions of workers. i mentioned one of the pleasing things about al and robotics, and that is what's known as moravec‘s paradox, that what we're incredibly bad at, as individuals, machines tend to be very good at. complicated sums, rapid and incredible access of memory from a database of a kind that we could never do, sorting and swapping of information and cataloguing and things like that. but things we can do without even thinking, like walk across the room or pick up a glass and have a sip of water, machines are hopeless at that. but that's fine, because we don't want them to do that for us. where it gets difficult is in medium

sort of service jobs, i think. stephen fry, what is intelligence? well, you could go the etymological route, and you could say it is a means to read into. legere is read and inter, interleg, and that's pretty good, actually, reading into things. in other words, pattern recognition. just being able to see connections in things and people are talking about the moment that we arrive at agi, artificial general intelligence, and that's when the various types of pattern recognition, you know, numbers, data, you know, certain faces and things like that, they all come together so that they can be intelligent across these different things. if you've got an artificial intelligence that's good at that and another one that's good at that and you get enough of them, and then you put something on top that goes, "oh, you want to know about a language problem, i'll dial up that one." surely, just a collection of specialists of intelligences

under one umbrella is a generals intelligence. it doesn't have to be a breakthrough, itjust has to be a collection of specialists. yes. i think you're very right, spencer. i think that's very likely to be the way it goes. it's reward is similar to our reward system which is really chemical, isn't it? it's tryptophan and serotonin and endorphins of various kinds that reward us and then we have a pain system to deter us, and there's nothing to stop us giving that to a machine. stephen, thank you so much for your time. such a pleasure. thank you for having us at your place. and keep clicking, i love it. thank you. that is it for this short carte of leg. the full—length version is an eye player. you can follow us on facebook for loads of extra content as well. al—hoceima hello and welcome. later on the programme... jeremy corbyn

comments went down well but was that because the audience was not well represented or did the bbc handle the programme rob lee? and where these pictures worthy of the attention they received? first, election campaigns are often defined by actual or perceived blunders but politicians caught on camera and microphones replayed endlessly increasingly so in the media social media age. jeremy corbyn had this encounter on tuesday. how much will it cost to provide a means tested childcare for 1.3 million children. it will cost... it will obviously cost a lot to do so... i presume you have the figures? i will give you the figure in a moment. you do not

know it? you are logging into your ipad. you're announcing a major policy and if you do not know how much it will cost. it featured on bbc but many viewers felt that too much was being made of a memory lapse... another few recorded