By Mark Savage
Entertainment reporter, BBC News
The news that Top Gear presenter Richard Hammond has been seriously injured after crashing a jet-powered car during filming is bound to raise questions about the show's future.
Richard Hammond has presented Top Gear since 2002
In the past, the motoring programme's high-octane stunts have drawn criticism from MPs, who said in 1999 that the series was "obsessed with acceleration".
Road safety campaigners even called for the anarchic show to be scrapped last year, claiming it "glamorises speed" and encouraged a "yobbish" attitude among drivers.
But Top Gear has not always been the petrol-headed programme that it is today.
It began as a local show on BBC Midlands in 1977, presenting an uncomplicated look at motor cars and road safety issues.
A year later, it transferred to national TV, with Angela Rippon as host in an attempt to broaden the programme's appeal to women.
It became so successful that it ran for another 23 years with almost no changes to its format.
Angela Rippon was one of the first Top Gear hosts
Along the way, it introduced viewers to TV presenters including Noel Edmonds, Quentin Willson and female racing driver Vicki Butler-Henderson.
But it was the appointment of Jeremy Clarkson, then a columnist at Performance Car magazine, in 1988 that forever changed the show.
His brand of outspoken, macho humour gave Top Gear a more abrasive edge and contributed directly to viewing figures rising from several hundred thousand to more than six million.
But not everyone was a fan.
Clarkson's scathing reviews could make or break a new car, and the presenter quickly became the scourge of motor manufacturers.
The host claimed he would "rather have bird flu" than a Corvette Z06, and when he described the Toyota Corolla as "dull", the company banned him from test-driving their cars.
Much to their relief, Clarkson decided to leave the show in 1999 to pursue other projects.
"I'd taken Top Gear as far as I could," the presenter told the Sun, although he admitted he would miss the show.
"I remember thinking life doesn't get much better than this for someone who loves cars," he said, recalling a week in Italy test-driving Ferraris, Lamborghinis and Bugattis.
The programme didn't fare well after Clarkson's departure. Viewing figures fell, and another presenter, Brendan Coogan, quit following a conviction for drink-driving.
Jeremy Clarkson's acerbic wit revitalised the programme
In 2001, the BBC decided to rest Top Gear and review the format.
As a result, the entire presenting and production team decided to take the show to rival broadcaster Five, where it was relaunched as Fifth Gear.
But just before the new show launched, the BBC announced Clarkson was to return with a revamped Top Gear show.
Expanding to fill a 60-minute slot, the programme became more focused on entertainment - and featured races, celebrity challenges and the regular destruction of caravans.
It also attracted controversy for its outrageous stunts.
The BBC had to apologise and pay damages to a parish council in Somerset after Clarkson rammed a pick-up truck into a chestnut tree.
He was apparently testing the vehicle's strength at the time.
Environmental campaigners also complained that the presenter had damaged a sensitive peat bog whilst driving a 4x4 to the top of Ben Tongue mountain in Scotland.
A BBC spokesman claimed the test-drive was carried out on private land with the owner's permission and that no damage was caused.
Nonetheless, pressure group Transport 2000 called for the show to be taken off the air and replaced with a programme that promoted "sensible driving in sensible vehicles".
Despite such complaints, the new format was a massive success with Richard Hammond joining the show in 2002.
It is currently shown in more than 100 countries around the world, and Top Gear magazine is the UK's biggest-selling car magazine.
"It's tremendously popular," says the magazine's editor Michael Harvey.
"We know that the show is the most pirated TV show in the world, beating programmes like Lost and Desperate Housewives.
"On [video website] Youtube, before the BBC asked them to take the clips down, one video of Jeremy had 938,000 downloads."
The programme even won an international Emmy in 2005, but car manufacturers continued to worry about the show's influence on the motor trade.
Some workers blamed Top Gear for the closure of Vauxhall's Luton plant
"Speak to anybody who used to work at Vauxhall in Luton," says Mr Harvey, "and they totally blame Jeremy Clarkson for General Motors closing the Vauxhall plant."
The reason for their anger was a review of the company's Mark One Vectra, in which Clarkson remained mute and drummed his fingers on the roof of the car for a full minute.
"He simply had nothing to say about it," says Mr Harvey, adding that there were many more complex reasons why the manufacturing plant was eventually shut down.
The new Top Gear was getting ready for its ninth season when Hammond was injured.
The presenter was thought to be driving at about 300mph in a rocket-powered dragster when he crashed on Wednesday.
He is currently being treated in Leeds General Infirmary, where he has been visited by co-presenters.
Hammond was thought to be attempting to break a speed record before he crashed
The BBC and the Health and Safety Executive will investigate the crash, and it is likely the programme - and its stunts in particular - will come under close scrutiny.
The broadcaster could not say on Wednesday whether plans for the new season would be affected by the accident.
"The new series is scheduled for October, but given the circumstances it is too early to confirm transmission dates," said a BBC spokeswoman.
"I don't think it's time for navel-gazing and looking at the future now," says Mr Harvey. "The only reaction is to be incredibly concerned for Richard."
"But up until this time yesterday, the future for Top Gear was incredibly rosy. I don't see any reason why it should have changed."