As Britain waited for a Nazi invasion in the summer of 1940, a select group of men prepared to meet the enemy with lethal eccentricity. Their weapons included two longbows and quivers of arrows dipped in a deadly poison that the brigade’s leader had discovered while exploring the Amazon jungle.

His name was Peter Fleming, and he led the Resistance Army of Kent and Sussex — a ruthlessly determined band of about 20 guerilla units whose sole aim was to kill as many Germans as possible. None of them was expected to survive: they were expendable and at the same time indispensable, if the invasion was to be repelled.

Fleming hoped that, by striking silently along the lanes and woodland tracks south of London, they would create a fear of a ghost-like army of English archers among the enemy. It was just one of an extraordinary and surreally creative arsenal of ideas designed to throw German High Command into confusion. This unorthodox and merciless approach to warfare would later be reflected in some of the most famous thrillers and action films of the 20th century . . . because Peter Fleming was the beloved elder brother of the novelist Ian, creator of James Bond.

Action and words: Peter (left) and Ian Fleming (right) when they were both young boys, Peter would grow up to a world of espionage more dramatic than the books his brother would later come to write

The ruses and the ruthlessness Peter Fleming used were quintessential Bond. So was his devil-may-care attitude to mortal danger and, above all, his readiness with a quip. If any man personified the real Bond, it was Ian Fleming’s brother.

Peter Fleming’s other plans for stopping Hitler’s shock troops included mining bridges and booby-trapping houses, lobbing home-made bombs or Molotov cocktails, and turning countless members of the public into potential resistance fighters — willing to press a switch and blow up the enemy when the moment came.

He and his second-in-command, ‘Mad’ Mike Calvert of the Royal Engineers, became renowned for their reckless disdain for danger. When a group of VIPs visited their headquarters at a farmhouse called The Garth, near Canterbury in Kent, the bigwigs were alarmed by the arrangements for dinner.

Their table was a crate of gelignite. As the evening wore on, Fleming casually lit a few candles which dripped wax onto the box. The senior officer, General Sir Andrew Thorne, remarked drily, ‘I see you like to live dangerously.’

Fleming explained how effective resistance could be possible only if the guerillas constructed elaborate underground hideouts, well stocked with rations, water, wireless transmitters and explosives.

Work had already started on a score of bunkers, excavated and ventilated by the Royal Engineers. Some were hidden in the cellars of houses. One, in the corner of a deer park, appeared to be a former hangar for a secret airship from the last war.

To show Thorne what he meant, Fleming led him into woodland overlooking the town of Charing. In the dark, the lieutenant challenged the general to find the entrance to a concealed resistance shelter. The officer searched for several minutes before Fleming nonchalantly kicked a tree stump.

It tipped back, revealing a hole with a rope ladder dangling into a cavern that had been enlarged from a badger’s sett.

In this cave, sitting on kegs of explosives and surrounded by weapons, booby traps, a radio and tins of emergency rations, were about ten grimly silent soldiers.

But this wasn’t the Resistance Army’s most flamboyant coup.

Determined to prove that British command centres were vulnerable to attack by German spies, Fleming and Calvert broke into the grounds of General Bernard Montgomery’s HQ and attached sticks of gelignite to his flowerpots. The notoriously prickly Monty took it well.

Peter Fleming was born in 1907, second son of Valentine Fleming MP and his wife, beautiful socialite Evelyn St Croix Rose. When Valentine was killed on the Western Front, Peter was ten years old. His father’s death prompted Winston Churchill to remark that seeing such brilliant men destroyed was like watching the lights of a dazzling city going out one by one.

After excelling at Eton and winning a scholarship to Christ Church, Oxford, where he earned a first in English Literature in 1929, Peter was sent to America by his family to serve an apprenticeship with a firm of stockbrokers, in preparation for joining the family merchant bank in London.

Not long after he arrived, Wall Street collapsed. Young Fleming found an excuse to avoid the financial chaos and go hunting in Central America, before dutifully reporting to the London bank.

Within two months he realised he couldn’t bear the life of a banker, and instead turned to adventure — answering a newspaper advertisement seeking two applicants to ‘explore rivers Central Brazil, if possible ascertain fate Colonel Fawcett’.

Percy Fawcett, a friend of novelists Rider Haggard and Sir Arthur Conan Doyle, had vanished in the Mato Grosso region with his son Jack while hunting for the mythical golden city of El Dorado. One rumour said the adventurer had been plucked from his canoe by a giant anaconda. Another claimed he was living as a guru with a tribe of Amazon natives.

Fleming failed to find him, but he did send back a sheaf of humorous essays, sketches and stories published in newspapers and books that made him a literary celebrity. Treating his expedition as a grand caper with liberal dollops of laid-back insouciance, he wrote that his adventures were hampered from the start by a revolution in Sao Paulo that flung Brazil ‘into a state of pleasurable excitement’.

After weeks of canoeing down rapids, he cheerfully admitted to readers that his ‘swanning’ had been ‘slapdash and unprofessional’.

Until Fleming published Brazilian Adventure in 1933, travel writers had been serious-minded, pompous and boastful. With a single, sustained burst of self-mockery, these memoirs blew the genre sky-high. The writer J.B. Priestley called it ‘the best travel book I have read for a long time’ and an eager public agreed.

But Fleming also won other fans, who saw other uses for his light-hearted approach to travel and adventure. He was the ideal foreign agent. He was interviewed by Major General Frederick Beaumont-Nesbitt, deputy director of Military Operations And Intelligence, as a candidate for the War Office’s ‘irregular warfare’ wing, Military Intelligence Department One (Research) — usually called MIR.

Peter Fleming, as he appeared while in Mato Grosso, Brazil in 1932 years before war would be declared

Heading to Russia for a national newspaper, he travelled by train on the Trans-Caspian and Turkestan-Siberia railways, sending back vivid reports: ‘Women in long-waisted coats of many colours, men whose stature is increased by fantastic fur hats, kneeling camels and tiny donkeys, piles of melons and gigantic grapes.’ Decades before travelogue TV, these were mesmeric accounts.

But he also delivered a blunt analysis of life in the Soviet Union under Communism and the dictator Josef Stalin, where ‘public opinion is rationed and distributed like bread’, and whose ‘170 million citizens are governed by fear . . . Soviet citizenship is a life sentence against which appeals are very rarely successful.’

In 1935, after returning from India, he married the actress Celia Johnson, who would later star in the British classic film Brief Encounter. Two years later the couple set off on a tour of Paris, Rome, Prague, Vienna, Berlin and Moscow, before heading east to China, which was at war with Japan.

By now it was plain that Britain would be dragged into war with Germany too, and back in London, Fleming reported to MIR for training.

Given the rank of acting captain, he had quite accidentally become a founder member of what was to be the Special Operations Executive [SOE], the top secret wartime unit dedicated to sabotage and subversion whose mission, in Churchill’s words, was to ‘set Europe ablaze’.

MIR was a hothouse of unconventional ideas. Operatives were issued with three pamphlets: The Art Of Guerrilla Warfare; the Partisan Leaders’ Handbook; and How To Use Explosives. Fleming was posted to the Africa and Asia Group, with two other agents — including Ralph Greg, a barrister and former Black Watch officer who had lost a leg on a big game hunting expedition 11 years earlier.

A wayward series of assignments followed, from kitting out resistance cells in Kent (complete with those poisoned arrows) to writing reports on the likelihood of war in the Far East: with prescient insight, Fleming warned that the Japanese would attack Allied troops before their government had declared war.

Instead of being sent to India’s frontier as he hoped, Fleming was despatched in 1940 to Nazi-occupied Norway to prepare for commando landings. It was his most dangerous mission yet: he had no idea whether he was about to walk straight into German arms.

Yet with typical levity, he had time to deliver a comic novel to his publishers before leaving. The Flying Visit imagined a propaganda flight by German High Command over Britain that goes awry when a saboteur’s bomb explodes on board, forcing Hitler to bail out. Parachuting into the grounds of a country house, der Fuhrer is captured by Jennings the butler, who locks him in the lavatory.

From Norway he was sent to Egypt, to scour the prisoner-of-war camps looking for Italian anti-Fascists willing to side with the Allies and take part in secret operations against the dictator Mussolini. With £40,000 in notes and gold sovereigns, and ‘a charter to collect and train a band of anything up to a thousand Italian desperados’, he and a team of men set to work recruiting in the PoW camps around Cairo.

It quickly became plain, though, that they would find no takers. Very few captured soldiers were remotely interested in Fleming’s unconventional work.

Instead, he went to Greece ‘with a quantity of demolition stores and booby-trap devices, and 20 Thompson submachine guns’. With this armoury he intended to help thwart any German invasion.

The despatches he sent back often read like comic novels. He described how he and his men, ‘by now attached to nobody in particular’, blocked bridges, blew up buses, fired Tommy guns at aeroplanes and destroyed an entire goods yard full of rolling stock by commandeering a steam engine and repeatedly crashing it at speed into the carriages.

During the evacuation from Athens, his boat was repeatedly strafed and then bombed by three German planes.

Fleming, who was enjoying ‘gin and lime on the bridge and a delicious omelette’, fought back with a Lewis machine gun. He noted that the planes were coming in ‘at the height of a driven partridge’.

Describing the explosion that sank the boat, he said: ‘I suppose my tin hat fell off, as a hunk of the ship fell on my head and made a cut which I noticed later because of the blood.’ He discovered he had been hit in the shoulder, too, but insisted it didn’t hurt.

He and his men scrambled ashore to safety on a Greek island, where their wounds were tended by locals.

A year later he was in India, tasked by the Commander-in-Chief Wavell to find a way of fooling the Japanese into supposing the British forces were much stronger than they really were. Fleming came up with a ruse codenamed Operation Error, a faked car crash. Wavell’s staff car was abandoned close to the Burma front, overturned on a corner as if the driver had approached too fast, skidded and lost control. Fleming intended the enemy to think that, fleeing from Japanese pursuers, the chief of the British Army in India had panicked and left everything behind, including his letters.

In it were pages written by Wavell himself, with ‘top secret information’ that suggested Army numbers were twice their real size, as well as giving details of a mysterious ‘secret weapon’.

On a reconnaissance sortie to plan where this decoy should be staged, Fleming ran into a party of British commandos engaged in a running battle with the advancing Japanese. To his amazement, this unit was commanded by ‘Mad’ Mike Calvert, the friend who had once helped him tie gelignite to Monty’s flowerpots.

Calvert and his men, ‘a scratch battalion of odds and sods, including several lunatics and deserters’, joined forces with Fleming. They took the car and crashed it close to the river at Sagaing in Burma: ‘Highly unsensational,’ he reported laconically. ‘We drove the Ford over the embankment. It remained the right way up with the engine still self-righteously running. We laughed and followed it up. Arranged contents, punctured tyre, let wind out of another, inflicted minor internal damage (not very logically).’

Then they made their escape in darkness over a bridge that was due to be blown up at midnight. ‘It all felt rather tame,’ Fleming complained.

In his report, written as usual with plenty of jokes and no military jargon, he pointed out that, ‘Sherlock Holmes, had he been promptly on the spot, could without difficulty have deduced from the skidmarks that there was something fishy about this supposed accident’. Whether the enemy were fooled, he decided, no one would ever really know.

It did impress the Commander-in-Chief. Wavell wrote a note of thanks: ‘My dear Peter, I hope it all puzzled the Japanese. When I am old and garrulous and blimping, I shall probably tell a story of how I tricked the Japs and saved India from invasion!’

Encouraged, Fleming dreamt up similar ruses. He threw a haversack crammed with false documents out of an aeroplane, and left a dead carrier pigeon on the border between China and Burma, with a message strapped to its leg listing a radio frequency for a non-existent agent: Fleming hoped the Japanese would try to make contact.

The man with the golden gun? Fleming's exploits might seem like they've been embellished with some of his brother's Bond stories, yet they are all true

He wanted to try the same trick with a human body but ‘surprising as it may seem,’ he reported flippantly, ‘in a country of 400 million inhabitants and in the middle of a major famine, it proved extraordinarily difficult to procure a corpse’. The plan, codenamed Operation Fathead, had to be repeatedly postponed.

Eventually a suitable body was found and flung out of a plane over enemy lines with a faulty parachute, to make it appear as though the spy had been killed by the fall. The Japanese found him but apparently ignored all the fake information they recovered.

As one wag remarked darkly, when this ruse was tried successfully in Europe, the body was dubbed ‘the man who never was’. The Burmese version was ‘the man who never did’.

By 1944, however, Fleming was a master at this sort of deception. He devised a range of special effects recordings that sounded like attacks of all kinds. To simulate large-scale assaults, he had the noise of tanks advancing, craft coming on shore in waves, and landing troops clearing the jungle with bulldozers.

For fooling the enemy into expecting a commando assault, he played sounds of paddles splashing in the water, boat bottoms scraping on the shore, footsteps on shingle and seaweed crackling underfoot.

When a commando attack was underway, he could mask it with the racket of ships’ engines in reverse, anchor cables running through hawse pipes, winches, landing craft engines revving up, orders given in whispers and loud voices, the clink of weapons and small arms fire, building up to mortars and demolition charges going off.

His aim was to keep the enemy in a constant state of jitters and confusion, and he often achieved it with a flourish of humour. He had retreating troops leave a handful of letters, including one that detailed false military plans, inside a copy of a pornographic magazine.

In Rangoon, Burma, he had agents spread a salacious rumour: ‘The Emperor of Japan is NOT a monkey but he and all his family have short, furry tails of which they are very proud.’

This childish joke was said to have sent the Japanese Kenpeitai (military police) into a state of apoplexy that lasted days.

It might seem as though the irrepressible Peter Fleming was having the time of his life. But when the fighting was over, he confessed to his wife, Celia, ‘After all the muddles and squabbles, and changes of plan and hurried flights hither and thither, I feel as if I’ve just woken up from a particularly horrible nightmare.

‘I am glad it is all over. I don’t think I ever allowed myself to realise how badly I wanted the war to end.’

Adapted from Master Of Deception: The Wartime Adventures Of Peter Fleming, by Alan Ogden, published by Bloomsbury Academic at £20, © Alan Ogden 2019. To order a copy for £16 (20 per cent discount) call 01603 648155, p&p free. Offer valid until 26/09/2019.