Thursday, 9 May, 2002, 00:37 GMT 01:37 UK
The name's Tricycle, Agent Tricycle
File of Dusko Popov, code named Agent Tricycle
Agent Tricycle's file contained his formula for invisible ink
Documents charting the secret life of spies and double agents as far back as World War I have just been released for public viewing.
BBC News Online's Claire Hills visited the Public Records Office in London's Kew and encountered the case of one of the more colourful spies to serve British interests.
There was only one appropriate codename for a playboy double agent who had a penchant for ménage a trois.
But although Agent Tricycle may have come across as an early James Bond-type, he was vital to Britain's intelligence gathering and, some say, the country's most important agent.
Born Dusko Popov, into a wealthy Yugoslavian family in 1912, he was recruited by MI5 to run as a double agent between 1940 and 1944.
Communicating by wireless, invisible ink postcards and a special code of microdots, he convinced his German employers that he was passing them important British military intelligence - but in fact all he gave them had been carefully cleared and construed.
In peace time, he spends a month or more of every year in Paris as he is very fond of the society of attractive women
British Army assessment
His regular room at the Savoy in London and his "appreciation of the ladies" earned him a reputation as a playboy and, until his liking for three-in-a-bed romps was revealed, he was simply named plain old Agent Scoot.
One typed record from Major T A Robertson tells how on Christmas Day in 1940, he and Tricycle met for lunch at the capital's upmarket society restaurant Quaglinos.
The pair then went to the Lansdowne Club in Berkeley Square to play billiards, before heading back to the Savoy for "dining".
It reads: "I think he (Tricycle) enjoyed himself thoroughly once he took part in the Christmas bonhomous rioting, well lubricated by champagne.
"We were picked up by a couple by the name of Keswick who took us to the Suivi nightclub where we danced.
"Early in the morning, we returned to the Savoy, both viewing things through rose-tinted spectacles."
Under the heading "most secret," one part of Tricycle's file outlines how he was given a questionnaire on British arms and weaponry by a German officer and asked to gather the answers.
It asked what was being constructed at various factories in Weybridge, Wolverhampton and Dartford and for "exact details" of the "guns and apparatus" belonging to the British military.
It wanted to know about fighter squadrons, how many Spitfires and Hurricanes the British had, and what the Army's armoured division consisted of.
Each time, British officers would construct realistic, though inaccurate, answers for Tricycle to deliver to them.
His formula for making invisible ink is also in the records. Aptly, he mixed it in a wine glass.
Photo of Agent Tricycle with photo of woman
The British spy had a reputation as a playboy
Tricycle's files - which number more than a dozen - are packed full of dated documents, invisible inked postcards, airmail letters stamped with "opened" and "examined", letters to his girlfriends - naturally sent "On His Majesty's Service" - and minute-by-minute accounts of his movements.
The agent, who spoke English, Italian, French and moderate German, also described Allied bomb damage to German cities.
In one account, he said the harbour at Hamburg had been hit, but it could still be used. Hanover, he said, had "suffered badly".
'Intelligent and cultured'
In a summary of the man, one British Army officer said Tricycle lost "no opportunity of disparaging the Germans" and had at one point in 1941 said he was "convinced Great Britain will win the war within two years, due probably to German's moral and economic collapse".
He is described in one missive as an "intelligent, cultured" man.
It goes on to say: "He has personality and charm and would feel at home in society circles in any European or American capital, being much the usual type of international playboy.
How to make invisible ink
Take one small portion of crystals
Pour into a wine glass
Fill it three-quarters full of water
Ensure the water contains no chlorine as it discolours the paper
To develop - rub out writing on postcard or letter
Iron until the paper turns brown
Black ink will stand out on brown paper
"In peace time, he spends a month or more of every year in Paris as he is very fond of the society of attractive women."
Tricycle refused payment from the British secret service saying he was happy to work for a country for which he had "whole-hearted admiration" and that his payment from the Germans was enough.
But MI5 did, on occasions, have to bail him out.
As one record puts it: "On Friday 14 March 1941, I met a somewhat tired Tricycle for luncheon at the Savoy when he told me he had discovered that he had not enough money to pay his bill.
"From this, it would seem that his previous evening must have been a somewhat expensive one."