David Shayler, a former MI5 officer who served from October 1991 to October 1996, disclosed classified material to The Mail on Sunday in August 1997. The documents allegedly showed MI5 monitoring left-wing groups and vetting Labour politicians, including Peter Mandelson, Jack Straw, and Harriet Harman. Shayler also alleged that MI6 had funded a 1996 Libyan Islamic Fighting Group operation to assassinate Muammar Gaddafi for £100,000 without Foreign Secretary Malcolm Rifkind’s authorization. According to his account, the bomb struck the wrong vehicle and killed civilians; the source does not independently establish those allegations.
After France rejected a British extradition request as politically motivated on 18 November 1998, Shayler returned to the United Kingdom in August 2000. He was charged on 21 September 2000 with three breaches of the Official Secrets Act 1989, including disclosing information derived from a telephone intercept. At trial, Judge Alan Moses ruled that a public-interest defense was unavailable and directed the jury that the disclosures remained criminal; Shayler was convicted and sentenced in November 2002 to six months, serving time at Belmarsh and Ford prisons. The case underscored the limited legal protection for intelligence whistleblowers in Britain, while the underlying MI6 allegations remained contested.