Book to reveal details of MI6 agents and Gaddafi death plot

Lecturer's study of special spying operations will describe material that Government has been trying to suppress

The Government faces a new challenge to its crackdown on intelligence leaks when a book on MI6 is published today, revealing the names of many British intelligence officers.

The 880-page book MI6, Fifty Years of Special Operations, is written by Stephen Dorrill, an intelligence historian and lecturer at the University of Huddersfield. It details top-secret operations, including assassination plans against Colonel Muammar Gaddafi of Libya and Yugoslavia's President, Slobodan Milosevic, publication of which the British Government has been trying to prevent elsewhere.

Mr Dorrill said that government lawyers had been in touch with the book's publishers, Fourth Estate, and had requested to see the material. "The publishers rightly refused," he said. In the book, Mr Dorrill gives detailed accounts of allegations by the disillusioned former secret agents David Shayler and Richard Tomlinson, both of whom are subject to injunctions preventing them having their claims published. The author denies he has breached the injunctions and says he has not spoken to either man.

"The information has been in the public domain. If not here, then in other parts of the world, or the Web. As far as our lawyers are concerned, that makes it acceptable to publish. The Government do not have a legal leg to stand upon," Mr Dorrill said. "As I say in the book, MI6 will have to face up to a new world where information is published in places like the internet. They are going to have to get used to the idea that they can't keep cracking down on the journalists and writers."

Ministers have mounted a concerted campaign to stop further leaks from Mr Shayler, the exiled M15 officer. In recent weeks, government law officers have issued writs for damages against him and The Mail on Sunday, which first published his allegations. A judge at the Old Bailey is expected to rule today on an application against The Observer and The Guardian by the Metropolitan Police Special Branch,which says it is investigating "serious breaches of the Official Secrets Act", and wants the newspapers to hand over journalists' notes, documents and e-mails relating to Mr Shayler. The papers are opposing this.

Mr Dorrill's book identifies current MI6 officers who have taken part in questionable activities of the service. Many correspond with the 115 names that were mysteriously posted on an American website last year. Mr Tomlinson was suspected of being responsible for the leak, but denied it.

The MI6 Balkan specialistwho wrote two articles for The Spectator magazine in 1994 under the pseudonym Kenneth Roberts is also identified. The articles argued against Western policy in the Balkans and were perceived as pro-Serb.

The book claims that the former South African president Nelson Mandela has had links to MI6. "It is understood that on a recent trip to London he made a secret visit to MI6's training section to thank the service for its help in foiling two assassination attempts directed against him."

Mr Dorrill also claims in the book that MI6's "biggest secret" is that ministers and MPs are being misled over the real size of the service's budget. "It is at least double the official figure," he says. He cites a former MI6 officer "with access to the internal accounts [who] puts it as high as five times this figure." The official figure is said to be £140m per year.