Sir Henry Birkin and his supercharged Bentley 'Blower'

Sir Henry Birkin raced at Brooklands regularly in the 1920s and early 30s

The export of the world's most expensive Bentley has been put on hold by the UK government, which has described the 1929 car as of "outstanding significance". But what do we know about the legendary "Blower" and the enigmatic aristocrat, Sir Henry Birkin, who spent his fortune developing it?

"He was fearless and he was always in a hurry, with the result that on many occasions he was deprived of victory because the desire for speed overcame his judgement and the endurance of his car," The Times wrote of Sir Henry.

"Dangers, the need for caution, and the advantages of a waiting race were all sacrificed to the love of brilliant driving at high speed."

Sir Henry, who was known widely by the nickname Tim, was famed as a top racing driver, always dapper in his trademark silk neckerchief flapping in the wind as he tore around Brooklands, the Nurburgring or Le Mans.

Using the family fortune made through Nottingham lace, Sir Henry travelled the world, living the glamorous life of a 1920s racing hero as one of the "Bentley Boys".

But he did not drive to win - he raced for the love of speed and to improve the standing of British motorsport, according to his great-great-nephew Sir John Birkin - a filmmaker who worked on a 1995 drama starring Rowan Atkinson as Sir Henry.

"Sailing, shooting and cars was what he lived for and he spent, really, all the family money on it," Sir John said.

"He wasn't the sort of guy who won all the races, he was more concerned with maintaining the lap speeds and records.

"On one occasion, at Le Mans in 1928, he managed a lap with an average speed of 85mph. All on three wheels because one had blown out.

"That's the kind of guy he was."

Sir Henry was an unassuming, shy man who suffered with a stammer but his love of motors and speed began at an early age, according to Sir John.

Sir Henry "Tim" Birkin, who was always seen wearing his spotted silk neckerchief, was renowned for his speed and won the 1931 Irish Grand Prix at an average speed of 88.8mph

His supercharged Bentley "Blower" was recently bought at auction for more than £5m by a foreign bidder

Sir Henry, seen here in an Alfa Romeo, set the record at Brooklands travelling at 137mph in his Bentley on a deeply rutted and bouncy course

At the family home in Ruddington Grange, just outside Nottingham, he was bet £15 he could not design and build a vehicle which would make it all the way along the drive under its own power - about three quarters of a mile.

At every third along the route he was met by someone holding a £5 note - he used the money to buy his first proper car.

Severed head

When Sir John went back to the family house, long since demolished, he found a stable with the words "every day, in every way, faster and faster" daubed on a wall by Sir Henry.

And a favourite family tale involves Sir Henry driving a Bentley up the staircase of the Savoy Hotel during a glitzy dinner.

Despite the roaring 20s and living the life of a motoring hero, it was not all smiles - his wife left him, taking the children, after becoming tired of playing second fiddle to his driving.

And Sir John believes his relative would never have got into motorsport had it not been for the tragedies of World War I.

Crashes at Brooklands racecourse were frequent and often fatal

Sir Henry was commissioned into the Royal Warwickshire Regiment and then the Royal Flying Corps, the precursor to the RAF.

Like other men of his generation, his experience of war left him with a zest for life and no fear.

Racing drivers in the 1920s had a short life expectancy. According to his family, he was once racing at Brooklands when he saw an object bounce across the track.

He said to himself 'what could that be?' before realising it was a competitor's head - it had been severed in an accident.

Despite his own success on the racecourse and holding the record lap time at Brooklands in Surrey - regarded by some as the birthplace of British motorsport - Sir Henry felt British sports car-makers were falling behind their Europe competitors.

'Every schoolboy's hero'

It was this belief that drove him to try to persuade WO Bentley, then head of the luxury car company, to develop the supercharged Blower.

But the Bentley boss was not interested, and so Sir Henry chose to sink much of his own money, and that of several supporters, into developing the four-and-a-half litre supercharged Bentley.

It was a huge success on the track and he finished second at the French Grand Prix at Pau in the vehicle.

According to Bonhams, which sold Sir Henry's Bentley Blower at Goodwood Festival of Speed last year, a recent test drive revealed it was still "on song".

It was owned by the celebrated watchmaker and vintage car collector Dr George Daniels, and fetched £5,149,800 - sold to an anonymous bidder from outside the UK.

The car, and the man behind the wheel, were once the talk of a nation - it was the vehicle James Bond drove in the first novel Casino Royale.

"He was a big hero at the time, someone every schoolboy will have known about," Sir John said.

"I still meet men in their 80s who knew of him - they speak of him in awe and say they followed his story.

"He had the right image, was very English and very self-effacing.

"We just wish he hadn't spent all the money!"

Sir Henry's racing days, and spending, came to an end after an accident driving in the Grand Prix de Tripoli in a race which he ultimately finished third.

He suffered a serious burn to his arm that became infected and developed into septicaemia, a blood infection, which led to his death in June 1933, penniless and in a London nursing home.

He is buried in Blakeney, Norfolk.

The government has placed an export bar on the Birkin Bentley until 31 October in the hope someone in the UK can raise the £5,149,800 paid for it at auction.

That period can be extended to May 2014 if there is a realistic chance of the money being found.