18 April 2013 Last updated at 07:53 ET

Six of the London School of Economics students who visited North Korea with an undercover BBC crew have criticised the school for publicising the story.

The LSE had demanded the BBC withdraw Monday's Panorama because students had been used "as cover" for the trip.

In a letter to the LSE, students said they were "put in more risk" as a result of its decision to "go public".

The LSE denied going public, but said it knew it would be publicly identified once the BBC show was aired.

'Basic facts'

Three BBC journalists accompanied 10 London School of Economics students and spent eight days in the secretive state.

The university had criticised the BBC and Panorama, saying students had been put in danger because they were not fully informed. It called for the programme to be dropped and for a full apology to be issued.

But the BBC said the film was strongly in the public interest. It aired on Monday.

In an open letter to LSE director Craig Calhoun and chairman Peter Sutherland, the six students - Hoe-Yeong Loke, Mila Akimova and four unnamed others - said they "felt compelled to establish the basic facts of the case".

The students said they had been told that a journalist would go on the trip and they could risk deportation or detention.

In Beijing, on the eve of flying to Pyongyang, they learned the journalist was John Sweeney and that he worked for the BBC, they said.

"As adults, and moreover as students of international politics, we then made the decision to proceed with the trip," the letter said. They added that "nothing happened... which would indicate that we were put in danger".

"After our return, an agent for the North Korean government emailed all of us to say they had belatedly discovered that a BBC journalist was in our group, after watching initial BBC reports of the trip. That North Korean agent threatened to 'make public to the world and the international press the lies made in the name of LSE students'.

"In a second email sent to the BBC and copied to us, that agent wrote that 'We will ignore this incident if Mr Sweeney stops his journalistic activities regarding the LSE-DPRK visit. Otherwise if the related programme is broadcasted, I will be left with no choice but to expose all the real story and data.'"

The students' letter went on: "We have no objection to the broadcast of the BBC Panorama documentary... Our main consideration here was that the BBC agreed that the documentary would not reveal our names or that of the LSE.

"We feel that we have now been put in more risk than was originally the case, as a result of the LSE's decision to go public with their story."

'Impossible position'

Robin Hoggard, director of external relations for LSE, thanked the students for their letter and said he respected their understanding of the situation, but at least three of the students on the trip contested the BBC's account.

He said the students "were told enough to get you into trouble but not enough to let you make an informed decision about the risks".

"If the BBC had laid out the full risks and sought consent in writing, we suspect there would have been second thoughts... All 10 of you were deliberately deceived, by the BBC's own admission. You weren't in a position to give informed consent."

Mr Hoggard said LSE had not gone public with the story.

"The BBC put us in an impossible position. We knew that LSE would be publicly identified if any LSE students were recognisable on Panorama (several were). And even if they weren't, the North Korean regime had threatened to reveal the details of all of you on the visit, and how the journalists gained entry to North Korea by claiming to be LSE students or staff," he said.

He said that after the BBC made its decision to air the programme "we then had a duty of care to staff and students to warn them of the consequences, and later that day we did through an internal email".