He was born in St Petersburg, a subject of the last Tsar; his father was French, his mother Russian. His half-Slav ancestry betrayed itself not only in his faith, but also in his manners: he had enormous personal charm, yet could switch rapidly from kindness to severity.
He fought brilliantly in the French army in 1919 and again in 1940; and when France collapsed, he made his own way to London and volunteered instantly to go back to France as a secret agent. He maintained that the wide acquaintances he had made in the business world between the wars would be bound to provide useful intelligence.
Captain Dewavrin, later famous as Colonel Passy, the head of de Gaulle's Secret Services, took him at his word. Fourcaud set out in August, via Lisbon, and was at work in Marseilles by September, recruiting French socialists and radicals who would report what was going on.
All de Gaulle's early supporters were denounced at the time as far right- wingers; an accusation that did not in the least apply either to Passy or to Fourcaud. Fourcaud had had friends among the French inter-war intelligence chiefs; that did not make him a right-winger. Instead it gave him a few ideas about how his circuit, codenamed "Brutus", might work.
He went to Vichy, where he met among others Colonel Loustanau-Lacau, who was also busy setting up a quite different intelligence circuit, and was indeed a long way to the right in politics; he, who had met many brave men, said, long afterwards, that Fourcaud was outstanding even among them.
Fourcaud was back in London before the turn of the year and set off at once on his next mission, on 13 January 1941. He travelled again through Lisbon; charged both with continuing his intelligence work and (to Passy's annoyance) with an extra political mission as well, given to him directly by de Gaulle, of forming anti- Petainist groups in any Petainist circles he could find. But he held, quite properly, that it was a mistake to mix an intelligence mission with a political one.
It was perhaps fortunate that Fourcaud expended most of his vast strength of personality on keeping "Brutus" going. By March he had established tenuous wireless contact with London through a cumbrous set called "Romeo", and set up sub-circuits in Toulouse and Montpellier as well. He also got involved with some SOE agents who had blown up a power station near Bordeaux and needed help in crossing into Spain.
Politics were his undoing. On 25 August he went to call on Admiral Laborde, giving his own real name and rank (then Captain) as he did so, to ask the admiral for help in the Gaullist cause. He was shown the door, his name was reported to Vichy, and four days later he was arrested.
Colonel Paillole, the head of Vichy counter-espionage, already playing a double game, tried to keep him out of mischief. Lesser policemen who had arrested one of the SOE party and dug Fourcaud's name out of him tried to make trouble for him.
He fell ill and was moved to a prison hospital at Clermont-Ferrand, from where in August 1942 he managed to escape into Switzerland. From there he was brought out, via the French Riviera, in inconceivable discomfort; he travelled to Gibraltar with 89 companions in a 20-ton felucca and so back to de Gaulle's headquarters at Carlton Gardens. There he spent a useful year on de Gaulle's staff helping to articulate the national uprising for which the Gaullist hoped. In January 1944 he went back to France, as "Sphere", to lead the "Union" mission.
They travelled in plain clothes but took uniforms with them to impress the guerrilla leaders whom they met. Their object was to co-ordinate the activities of various maquis bands east of the River Rhone, particularly in the Vercors. The disaster that followed there was not Fourcaud's fault; well before it took place he had obeyed orders and withdrawn (again through Iberia) to London.
In the closing agonies of the Third Reich he went forward into Germany with his friend (Sir) Robin Brook to try and discover what had happened to F.E.E. Yeo-Thomas ("The White Rabbit"), an Anglo-Gaullist hero who had fallen into the Gestapo's hands. His fluent Russian saw them through several Red Army controls before they reached Buchenwald, from which Yeo- Thomas had escaped already.
After the war he went back to business but never forgot his Resistance friends - he came to London at the age of 93 to attend the funeral of one of his companions on "Union". He kept clear of professional politics, but was always ready to defend the reputation of the Resistance against revisionists - many of them ignorant of the facts of war and occupation - who sought to prove that it had all been a mistake.
Pierre Fourcaud, soldier and intelligence officer: born St Petersburg 27 March 1898; died Paris 2 May 1998.