London. The BBC has refused to drop a Panorama programme on North Korea after a students’ union said it used students "as a human shield” to film there.Three BBC journalists accompanied 10 London School of Economics students and spent eight days in the country.The LSE students’ union’s Alex Peters-Day said Monday’s programme should be dropped because students were lied to and could not give informed consent. But the BBC said the students had been properly warned ahead of the trip.Head of news programmes Ceri Thomas said the North Korean government was the only party the BBC had deceived."We have a duty to give enough information to people on a trip like this so they can give us fully informed consent,” he said."There were 10 students. We told them there would be a journalist on the trip and, if that journalist was discovered, it could mean detention and that it could mean arrest.”Nine of the students were aged 21-28 while one was 18, he said.‘Student welfare’The LSE complains the students had not been told there was an undercover team of three, filming a high-profile documentary.Panorama reporter John Sweeney spent eight days undercover inside North Korea for the programme, travelling with his wife and a cameraman.Thomas admitted they had initially been told it was one journalist but that, when they were in Beijing before they flew to Pyongyang, they were told there would be three journalists.He said North Korea  is one of the most oppressive regimes in the world, which is threatening nuclear war in the Korean peninsular.The "public interest arguments” for making and showing the programme were "overwhelming”, he added.He said three of the students had since asked "that their images be taken out” and that they would be "pixellated or blobbed.”LSE students’ union general secretary, Peters-Day - who was not on the trip - told the BBC News Channel: "One of the students made it absolutely clear that she was not made aware of what happened."For us, this is a matter of student welfare - students were lied to, they weren’t able to give their consent.”She said all LSE’s future research was "now at risk”."I think the trip was organised by the BBC as potentially a ruse for them to get into North Korea and that’s disgraceful.