It was one of the most interesting talks of its kind I have ever had. This was a man of the highest principle working on the land. Put there by the Conscientious Objectors' Board. We discussed at length the principle of warfare and the principles of Hitlerism. Cammaerts' motives were absolutely pure and, therefore, he was one of the most successful agents we ever sent into the field

He set off for St Jorioz near Annecy, where he was disturbed by the evident lack of security within the organization which he had been instructed to join. His suspicions were proved right when it was learnt that the St Jorioz group had been effectively penetrated by Hugo Bleicher of the Abwehr, the professional and therefore pro-Nazi German counter-espionage organization.

From such false starts as these, and indeed from another one in Cannes, where again he found the security alarmingly lax, Cammaerts, whose original cover-story was that of a schoolmaster recuperating after jaundice, gradually built up an organization. He did so by adhering strictly to the lessons he had been taught during his SOE training. Over a period of fifteen months he never spent more than three or four nights in the same house. He insisted that all those with whom he worked must at all times have a satisfactory explanation of their actions which they could produce if they were suddenly arrested. He made sure that whereas he could contact a large number of resistance workers very few knew how to reach him.

The wide area in which Roger had to carry our his duties involved him in much travelling. Many were the hairbreadth escapes, the lucky chances of that period, for travelling was the most unhealthy of pastimes. Only Roger's wide circle of friends saved him from certain arrest. Striding across the uplands, his tall figure caused the shepherds to call to each other, "voila Ie grand diable d'anglais", for among the simple, honest people of the region Roger's nationality could not be hidden. Not a man among them would not have fought to save Roger; not a woman who would not have hidden him from pursuit at the risk other life; not a child who would not have undergone any form of torture rather than betray I'ami anglais.

I didn't really find it a strain maintaining a false identity. Of course, you had to have a cover story covered by suitable papers that were able to explain why you were travelling in the way you were, so that if you were travelling in a car at night you had to be a doctor or an engineer or something like that.

You had to be certain that the people you were working with had the same understanding of security as you had yourself. You had to work through trusted leaders, that is to say every cell had to have someone whom you knew was loved and trusted by the people he was working with and you had to work through him or her and they had to accept your basic principles of security, which meant a whole lot of things including not using the telephone, not going into black cafes and eating huge black-market meals and that kind of thing. You had to make quite sure that the people you were working with understood those things which were dangerous to do.

I don't remember the pressure being something that I felt acutely except just occasionally when you were doing something which you knew you oughtn't to be doing, such as travelling by car with weapons and explosives in the back of the car. I had a close shave transferring some weapons and explosives from Avignon to the north of Marseilles, to a group who had got some work prescribed to do and they had no equipment and nothing to do it with. We were stopped at Senas, which was about halfway on the trip, by some SS troops. This worried us a lot because usually you were stopped and checked by the German version of the military police. Obviously there was a scare on. Pierre and myself were told to get out of the car and then they started to cut the seat material in the back of the car. Pierre, who spoke very good German, said, "What on earth are you doing?" They said an American bomber had been shot down and they were looking for the crew. Pierre said, "You don't think we've sewn them into the back seat, do you?" at which the Germans laughed. They didn't open the boot which was not locked and which was full of weapons. They just told us to get in the car and drive away.

Another way out of a problem was to spit blood and pretend you had TB. The Germans were very frightened of TB, and if you spat blood they tended to tell you to go on your way. Once, I got out of a train at Avignon station and there was a rather heavy control and they were spending a lot of time looking at my papers and I coughed and spluttered, bit my lip and spat blood on the platform, where it could be seen on the hard surface. My papers were returned very quickly and I was sent on my way.

Christine Granville who had for her own volition risked the death penalty, the responsibility must have been almost beyond endurance. For apart from the consideration of personal courage, she had also to decide whether from the SOE point of view her action was wholly permissible. As an individual she would not have hesitated to barter her life for the lives of three others. As an agent, however, she was obliged to assess the value of those lives against hers; and if hers proved to be worth more, it was her duty to keep it.

In the assessment she made it was Francis Cammaerts's life that weighed the scales in favour of the decision. Had not Francis Cammaerts been arrested with us, Christine would have been perfectly justified in taking no action if action meant jeopardizing herself. Indirectly, then, I owe my life to him as much as I do, directly, to her.

When Christine heard of the arrest she set off for Digne prison immediately. An elderly and kindly gendarme, whom she had approached with a request that she might be allowed to bring some necessities to her husband in prison, put her in touch with an Alsatian named Albert Schenck, who served as a kind of liaison officer between the French prefecture and the German Sicherheitsdienst. To Schenck Christine announced that she was not only a British agent but Cammaert's wife and, for good measure. General Montgomery's niece. The lesson she had learnt from her relationship with Admiral Horthy had not been forgotten. She also made the point that as Allied forces had now landed in southern France it would be very much in Schenck's interests to secure the release of Cammaerts and his fellow prisoners. Schenck told Christine that he himself could do nothing but that there was a Belgian named Max Waem who had more authority and might be willing to help. He did not think that Waem would be interested in any transaction which brought him less than two million francs.

Living and struggling from day to day within a community where total interdependence was the essence of everyday life, the singling out of individuals cannot give a picture of reality. Individual agents either in France or in Poland were dependent for every meal and every night's rest on people whose small children, aged parents, property and livelihood were continually put at risk by our presence. Their contribution involved a much greater sacrifice than ours.

Francis Cammaerts dismisses as 'a fantasy' the theory put forward by those like his one-time deputy Pierre Raynaud and the BBC's Robert Marshall that Dericourt was run by MI6. He thinks men like Bodington and Dericourt became double agents because 'they had a freak sense of adventure and thought it was a clever way to play it.'

One of the F Section agents recruited in the field, Jacques Bureau - Prosper's radio technician - also is convinced that the Prosper agents were used to deceive the Germans about the time and place of the invasion, but he sees it as an indispensable, a justifiable strategy for defeating the Nazis and saving countless lives. His attitude is one more of sorrow than of anger, an acknowledgment of the tragic ironies of the situation rather than an indictment of the British.

He believes that Suttill and Norman behaved honourably, following orders that were designed, although neither they nor the French Section staff were aware of the fact, to set up the radio games that, along with

Dericourt's passing of the mail, would keep the German forces in the north-west of France in a constant state of expectation of invasion there between the spring and the autumn of 1943, when they might have been used against the Allies on other fronts. Although they were unaware of it, as he sees it the weapons he and the other Prosper agents wielded were the lies that successfully protected the real invasion plans.

Training staff did not think highly of him and reported that he would make a competent sabotage instructor, but did not appear to have leadership qualities. He was sent into France on March 23-24 1943 to a field near Compiègne, where the Lysander aircraft that carried him picked up Peter Churchill, whose circuit Cammaerts was to assist.

The young men who drove him to Paris that night gave him a series of security scares; when he got to St Jorioz, near Annecy, where other leaders of the circuit were holed up for the time being, the set-up seemed to him dangerous and so he left.

He went down to the Riviera, gave it out that he was a French teacher recovering from tuberculosis, and watched how life under German occupation and the Vichy regime was run. Gradually, he built up his own circuit, codenamed "Jockey" by headquarters at Baker Street. He had one serious disadvantage for the secret life: 6ft 4in (1.93m) in his socks, he could not help catching policemen's eyes; but he had common sense, a strong love of France, an even stronger sense of security and an iron will.

He began by sounding out a few retired policemen whom, in turn, he got to watch and sound out a few more men and women on whom he hoped he could rely. Step by step, he built up reception committees, who could break curfew and receive drops of arms in remote country. He secured Auguste Floiras, a model of discretion, as wireless operator, through whom drops were arranged. In 15 months' activity, described in the official history as "flawless", Floiras sent 416 messages, a section record.

Once Cammaerts had received arms, he could start training. He left the Riviera for its hinterland, never staying more than two nights in the same spot. No one, not even inside his circuit, ever knew where he was going to be or how to get in touch with him: he got in touch with them. This enabled him to carry out important sabotage missions in spring 1944, and, after the Normandy landings in June, to interfere severely with German troop movements.

Once, driving in remote country, he was stopped by a chance SS patrol. They searched him and his car, found nothing and waved him on. They had not noticed that the car sat stern-heavy on the road, because its boot - which they forgot to open - was full of arms and ammunition.

Through a misunderstanding - nothing to do with Cammaerts - the Vercors plateau, south-west of Grenoble, declared itself independent on hearing of the Normandy landings, and Cammaerts was present when the Germans counterattacked in July. Sensibly, he slipped away instead of waiting to be slaughtered. He was made chief of all resistance forces on the left bank of the Rhone, with the rank of lieutenant-colonel, and helped to organise secret assistance to the Franco-American landing on the Riviera coast in mid-August.

Bad luck led him into German hands at a snap road control. He was recognised and sentenced to death; with astonishing courage, his courier, a Polish countess known as Christine Granville, bribed his captors to let him go. She was awarded a George medal, and he a DSO.