David Clarke, a lecturer in journalism at Sheffield Hallam University and author of Flying Saucerers: A Social History of UFOlogy, said opening the MoD's files would make it harder to sustain the idea that evidence for the existence of aliens has been suppressed. "The more of this stuff that they put on their website or put in the national archives, the less it will cost the taxpayer, because at the moment people are writing in about individual incidents and they are having respond," said Dr Clarke, referring to requests under the Freedom of Information Act.