Military victories, trade, missionary zeal, racial arrogance and a genius for bureaucracy all played well-documented roles in making the British Empire the largest the world has known.

Rather less well understood was the importance of the moustache.

A monumental new history, The Decline and Fall of the British Empire by Piers Brendon, promises to restore this neglected narrative to its rightful place in the national story.

Dr Brendon, a Fellow of Churchill College, Cambridge University, argues that colonial moustaches had a clear practical purpose: to demonstrate virility and intimidate the Empire’s subject peoples.

The waxing and waning of the British moustache precisely mirrored the fortunes of the Empire – blooming beneath the noses of the East India Company’s officers, finding full expression in Lord Kitchener’s bushy appendage and petering out with the Suez crisis in Anthony Eden’s apologetic whisps.

This analysis of the “growth of the stiff upper lip” is an essential strand of Dr Brendon’s epic 650-page political, cultural, economic and social history of the Empire, which is published on October 18. “It is a running gag in a serious book, but it does give one a point of reference,” he said yesterday.

In the 18th and early 19th century, sophisticated Britons wore wigs but spurned facial hair. The exception was the king, George III, whose unshaven appearance was mocked as a sign of his madness. However, by the 1830s the “moustache movement” was in the ascendancy. British officers, copying the impressive moustaches that they encountered on French and Spanish soldiers during the Napoleonic Wars, started the craze, but the real impetus came from India.

Just as British troops in Afghanistan today are encouraged to grow beards to ease their dealings with local tribesmen, so the attitudes of Indian troops under the command of East India Company officers in the first half of the 19th century altered the appearance of the British soldier.

“For the Indian sepoy the moustache was a symbol of virility. They laughed at the unshaven British officers,” Dr Brendon said. In 1854 moustaches were made compulsory for the company’s Bombay regiment. The fashion took Britain by storm as civilians imitated their heroes.

Dr Brendon writes: “During and after the Crimean War, barbers advertised different patterns in their windows such as the ‘Raglan’ and the Cardigan’.” Moustaches were clipped, trimmed and waxed “until they curved like sabres and bristled like bayonets.”

After 1918 moustaches became thinner and humbler as the Empire began to gasp for breath, even as it continued to expand territorially. It had been fatally wounded, Dr Brendon suggests, by the very belief in the freedom that it had preached. After the victory over Germany and Japan in 1945, independence movements across the red-painted sections of the world map, and Britain’s own urgent domestic priorities, meant that the Empire was doomed.

The moustache too was in terminal decline. “It had become a joke thanks to Charlie Chaplin and Groucho Marx. It had become an international symbol of ‘villainy’ thanks to Hitler’s toothbrush and ‘the huge laughing cockroaches’ under Stalin’s nose,” writes Dr Brendon. In Britain it was also synonymous with the “Colonel Blimps” clinging to an outmoded idea of colonial greatness.

In Eden’s faint moustache Britain’s diminished international status found a fitting symbol. It all but disappeared on TV and, moments before his broadcast on the eve of the fateful occupation of the Suez canal in 1956, his wife had to blacken the bristles with mascara. His successor, Harold MacMillan, was the last British prime minister to furnish his upper lip.

Harold Wilson, the self-styled man of the people, had been clean shaven since the 1940s, Dr Brendon notes. “He obviously believed that the white-hot technological revolution was not to be operated with a moustache.”

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