Sitting in the Air Ministry in London in 1943, Pearl Witherington longed to do something more for her beloved and broken France than simply pushing paper. Strong-willed, cool-headed and ferociously practical, the 29-year-old volunteered for the Special Operations Executive. After seven weeks of training she was parachuted into France to spend a year of danger and deprivation, becoming one of the second world war's most successful Special Operations Executive organisers of the armed resistance, with a million franc reward on her head.

She was an ideal recruit, according to the secret papers released yesterday by the National Archives. Pearl Cornioley, as she became, died in February and her obituaries told extraordinary tales of wartime courage: she commanded troops who killed 1,000 German soldiers, saw to the surrender of 18,000 more and organised and armed the resistance.

But the newly-released documents provide, for the first time, insiders' accounts of her remarkable heroism.

Brought up in Paris by her British parents, she spoke fluent French. Her training reports describe her as a woman who was "very capable" and "completely brave". She particularly took to sabotage lessons and guns - "probably the best shot (male or female) we have yet had".

Her night landing in the southern Loire on September 22 1943, with strong winds buffeting the RAF Halifax, did not bode well. She lost her two suitcases with all personal belongings. It was recorded in a debriefing later: "Informant never received sufficient clothes. Shoes were the greatest worry. Very."

At first using the name of Genevieve Touzalin, and with a cover story as a representative of a cosmetics firm, Pearl's job was to act as a courier for the resistance network run by Maurice Southgate.

Unable to find lodging she would carry messages "during long nights on cold trains". By February 1944 she was exhausted and convalesced for a month suffering from neuralgic rheumatism.

In May events took a dramatic turn. Southgate was arrested by the Germans and Pearl was transformed into a leader, eventually organising and supplying some 2,600 maquisards (resistance fighters).

At first they were a ragbag of farmers and she complained about the type and quantity of guns. Her most dangerous moment came a few days after the Normandy landing. "We were attacked by 2,000 Germans on the 11th June at 8 o'clock in the morning and the small maquis, comprising approximately 40 men, badly armed and untrained, put up a terrific fight, with the neighbouring communist maquis which numbered approximately 100 men."

The battle raged for 14 hours and the Germans lost 86, she recorded, and the maquis 24, "including civilians who were shot and the injured who were finished off". She herself fled to a cornfield until the Germans left the area. "I had been awfully hot in the blazing sun and frightened."

For the next four months she organised more than 20 air drops of weapons and supplies as her burgeoning army carried out sabotage operations on the German lines of communications.

After the war, Pearl was recommended for a military honour but, as a woman, she was ineligible. When she was instead offered the civil MBE she refused.

"There was nothing civil about what I did," she said many years later. In her letter of rejection, released yesterday, she said the offer was unjust: "The work which I undertook was of a purely military nature in enemy occupied country. I personally was responsible for the training and organisation of nearly 3,000 men for sabotage and guerrilla warfare."

For many years Cornioley refused to give an account of her life as she was afraid it would be distorted into a love story. Inevitably she has been compared to Charlotte Gray, the fictional character in Sebastian Faulks's novel.

It has been suggested that Cornioley, along with others including the extrovert New Zealander and resistance fighter Nancy Wake, may have been the inspiration. There are superficial similarities: for example, Charlotte joins the resistance to find her lost RAF lover, while Pearl linked up with her French fiance, Henri Cornioley, an escaped prisoner of war who became her second-in-command and married her after the war.

In an interview in 2002 she dismissed the idea with a typically bluff retort: "There was a job to be done. I didn't put my life at risk just so I could be with Henri."

"The truth about Charlotte Gray is that she was entirely invented. That's the way good novelists work," Faulks told the Guardian. "I had not heard of Pearl Cornioley when I wrote Charlotte Gray in 1995 but I read some obits of her this year. She was obviously a tremendous woman and a formidable agent but she has nothing whatever in common with Charlotte."

Pearl died in France in February this year at the age of 93, nine years after Henri. For her, the greatest award came only two years ago when the RAF finally presented her with her parachute wings.

The women of SOE

Founded in 1940, the Special Operations Executive was ordered by Winston Churchill to "set Europe ablaze" with the fires of resistance. Women volunteers - often recruited from the First Aid Nursing Yeomanry - were initially used as couriers on the grounds that they were less likely than men to be suspected of illicit activities. SOE's F Section, which covered France, sent 39 female agents into the field, of whom 13 did not return. Their exploits have been fictionalised in literature and cinema, including the 1958 movie Carve Her Name With Pride, in which Virginia McKenna played the SOE agent Violette Szabo. Szabo was flown into France twice in 1944, first to Cherbourg to organise a resistance group and secondly to Limoges, where she was captured. She was executed in February 1945, aged 23.