voice-over: this is bbc news. we'll have the headlines for you at the top of the hour, which is straight after this programme.

i am grateful that my father never really knew the extent of how he was duped.

auctioneer call

i first heard about

the zaks collection from konstantin akinsha and andrei vassiliev. from the very beginning, the story seemed hard to believe. we wanted to understand how paintings of such dubious origin could be sold as genuine works, and how did they end up on the walls of museums all around the world 7 one painting from the zaks collection unexpectedly appeared in a scene from christopher nolan's oppenheimer. a few months later, the same painting turned up in anotherfilm,

the wonderful story of henry sugar by wes anderson. i'm beatrice gimpel and i'm swiss and i'm partly french

through marriage, but i've lived here in london in the uk for 49 years — 49 very happy years. my parents, especially my father, were very interested in paintings and sculpture and from the mid—late �*60s, early �*70s on, he bought extensively anything he liked. and he did a lot of his homework inviting, talking to artists, so there was no doubt that what he bought was always first class. and after he died, when we had the first inheritance meetings, when one of the experts said that a whole range of paintings were dubious... ..we were absolutely shocked and we didn't believe it to start with.

so i'm currently sitting on flight 317, london to zurich, to go and look at the paintings which were willed to beatrice

by her parents, and my role, really, is to just see if the doubts that beatrice had are in any wayjustified. tell me about the lissitzky — how you acquired it and what sort of emotions it brings forth in you. so this was my grandfather who acquired it more than 20 years ago and i've been fortunate enough that the family lets me have it. and it's, i mean, at the end of the day, just a beautiful piece. i think the most important thing is that, during my grandfather's life, he believed it was a real, an original that he'd bought, and that's the most important thing. at the end of the day, i really would love it to be authentic, but it doesn't take away from the style, which does replicate lissitzky�*s.

so it doesn't change your feeling... were this information to become known, it wouldn't change your feelings regarding how you view the picture and what emotions it gives to you? no, because the reaction between a person and a painting is an emotional engagement you have with those shapes, those forms, those colours.

archive: adolf hitler, - the indomitable nazi leader, is now chancellor of germany.

inspired by his terrific driving force... amazing discoveries of lost paintings aren't all this fiction.

many lost masters have been found in attics, old country houses and the dusty storerooms of provincial museums.

so what we're going to do is use a high—resolution image of the subject's painting, run it through the machine, through the various algorithms that we have that allow it to be compared to a body of 20 original bona fide lissitzkys that we know are real. if that painting fits inside that cloud, inside that contour, we can say with 99% confidence that the painting is authentic. if it's outside of that cloud, we can be fairly confident that the painting is a forgery.

hello. well, some of us are in for a fine day. thursday's expected to bring warm, sunny spells to many northern and eastern parts of the country. certainly won't be like it everywhere — in fact, farfrom it in the morning across many western and southern areas of the uk. right now, a lot of cloud shrouding the uk. a weatherfront is crossing us,

bearing rain and dribs and drabs possible anywhere through the night and in some areas even quite heavy for a time. but this weather front is caught in a current of very mild air streaming in from the southern climes, quite a breezy end to the night is expected as well. but i think by the time we get to around 6:00 in the morning, you can see the skies are clearing across many eastern and some western areas of the uk as well. temperatures will be in double figures in most major towns and cities. so, here's the morning then, the forecast. you can see still a fair amount of cloud across some southern and western areas, dribs and drabs of rain, but already sunshine across, say, many northern and northeastern parts of the uk. the temperatures are very pleasant indeed — widely, i think, into the high teens or 20 degrees across england, eastern scotland, around 18 and out towards the west, around 14to17 degrees celsius. but the west will always be more cloudy. now into friday, the south

of the country is closer to an area of high pressure, so i think brighter skies here. but i say brighter, not necessarily all that sunny, because we still have that relatively mild and murky current southwesterly wind, in fact, bringing some outbreaks of rain to northwestern areas. so the sunny, brighter skies will always be further towards the east and south and every bit as mild or warm, 20 degrees widely in some areas — mid or high teens. now, that warmth isn't going to stick around. in fact, saturday night into sunday, we're expecting this slightly cooler air mass or much cooler air mass drifting in out of the west and the north atlantic and brought also by this area of low pressure, which is expected to sweep in some rain to many northwestern areas of the uk. so, yes, we've got three days of relatively mild, if not warm weather given some sunny spells, but by the time we get to sunday and certainly into monday, it's all change — colder and outbreaks

of rain from time to time. live from washington. this is bbc news.

the us vows to stand behind israel, as fears of a retaliatory strike from iran grow. the us and japan announce a new era of strategic cooperation, with the building of a joint air and missile defence system. and three months after gunmen took control of a live tv broadcast in ecuador, we look at how the country is cracking down on gang violence. hello. i'm carl nasman. an israeli air strike in gaza has killed three sons and four grandchildren of hamas's political leader ismail haniyeh. this video is believed to show him receiving the news in qatar, where he lives in exile. israel has confirmed the strike, describing the sons as "hamas military operatives". he's been actively involved in negotiations to broker a ceasefire with israel, but he says the killing of members of his family

will not change hamas's demands