The authors Graham Greene, Arthur Ransome, Somerset Maugham, Compton Mackenzie and Malcolm Muggeridge, and the philosopher AJ "Freddie" Ayer, all worked for MI6, Britain's Secret Intelligence Service admitted for the first time today . They are among the many exotic characters who agreed to spy for Britain, mainly during wartime, who appear in a the first authorised history of MI6. The book even reveals that the intelligence agency's deputy chief, Claude Dansey, was seduced by "Robbie" Ross, said to have been Oscar Wilde's first lover.

It describes the antics of Ecclesiastic, mistress of a German Abwehr military intelligence officer in Lisbon run by "Klop" Ustinov, Peter Ustinov's father. It also tells the story of how a Dutch MI6 agent, Peter Tazelaar, was put ashore on a beach near the casino at Schevening, The Hague, in evening dress, smelling of alcohol and wearing a specially designed rubber oversuit to keep him dry while landing.

Greene, Mackenzie, Muggeridge and others who have written about their secret work make it clear they were reluctant spies approached by MI6 because of their access and knowledge of exotic parts of the world. Others, such as Sydney Reilly, the self-styled "ace of spies", were more gung-ho. But in enemy-occupied Europe during the second world war, many, says Keith Jeffery, author of the official history, were "ordinary men and women" providing information on train or ship movements, for example, and would almost certainly have been shot if found out.

However, while MI6 officers and agents were given weapons training for self-defence, none was given a "licence to kill", according to a note headed "myth busting" distributed at today's book launch. Jeffery said he found no evidence of it in the MI6 files. He does, however, describe the valuable spying activities of Wilfrid "Biffy" Dunderdale, MI6's man in Paris before and during the second world war, who is said to be the model for James Bond. Dunderdale, a friend of Ian Fleming, a naval intelligence officer, is described as "a man of great charm and savoir faire" with a "penchant for pretty women and fast cars".

Jeffery said he found no evidence to support recent claims that MI6 was involved in the assassination in 1916 of Rasputin, the notorious "mad monk" who had insinuated himself into the Russian royal family. "All I can tell is what I found in the archives … If MI6 had a part in the killing of Rasputin, I would have expected to have found some trace of that," Jeffery said. The book does, however, refer to a colourful account of the murder by MI6's man in Moscow, Sir Samuel Hoare – a future government minister – who said he was "writing in the style of the Daily Mail" because it was "so sensational that one cannot describe it as one would if it were an ordinary episode of the war".

Hoare wrote: "True to his nickname ('the rake') it was at an orgy that Rasputin met his death." Jeffery notes simply that Rasputin "was murdered in the early hours of the morning of Saturday 30 December". In his recently published book Six, the author and journalist Michael Smith refers to a number of claims that Rasputin was shot several times with three different weapons "with all the evidence suggesting that [MI6 officer Oswald] Rayner fired the fatal shot, using his personal Webley revolver".

Reilly is another exotic character who appears in the MI6 history, which covers the period from the agency's establishment in 1909 until 1949. Shot by the Bolsheviks, Reilly came to grief by fatally combining politics with espionage, the book suggests. "Reilly was an MI6 agent. He also wanted to assassinate. That does not necessarily mean MI6 tasked him," Jeffery said. MI6 agents could be maverick and "off-message" and less valuable an intelligence asset as a result, he added. Before the D-day landings on 6 June 1944, MI6 officers discussed a co-ordinated assassination campaign in France, the book reveals. Bill Cavendish-Bentinck, chairman of the Joint Intelligence Committee, agreed with MI6 that it would risk bloody reprisals. Nevertheless, if the French liked to "assassinate Germans or collaborators", he added, "we should not deter them".

The official history also shows how Kim Philby, the most notorious member of the Soviet Union's five-member Cambridge ring of spies, was valued and trusted by MI6. Stewart Menzies, chief of MI6, refused a request in 1943 to get Philby transferred to work for the Foreign Office. "You know as well as I do the valuable work which Philby is doing for me," he told the FCO. "Trust is the intangible. Philby was part of the charmed circle," Jeffery said. The attitude towards Philby was that he was a "bit wild, but he's OK now", he added, referring to Philby's open communist sympathies at Cambridge University.