Born in 1923, his father Graham began taking his son around the race circuits of Europe when the boy was only a toddler.

After active service in the Second World War, Murray Walker forged a highly successful career as an advertising executive. The slogan "A Mars a day helps you work, rest and play" was not one he thought up, he insists.

The young Murray began his motorsport career by racing motorbikes, following in the footsteps of his father, Graham Walker. He had some success, winning the gold medal in the International Six-Day Trial in 1949, but then chose to move sideways into commentating after a spell in the army. Initially, he commentated on motorbike racing, working with Graham until his father's death in 1962. Murray progressed into car racing as the popularity of bike-racing diminished.

Until 1978, Murray was a part-time commentator, building up a successful career in advertising during the week and fitting in his commentating duties at weekends. After James Hunt's victory in 1976, the BBC decided to start broadcasting all of the Grand Prix, and asked Murray to become, as he has been since, the voice of Formula 1.

He is known for his enthusiastic, sometimes apoplectic style of commentating, often getting carried away with events and having to be corrected by his calmer sidekick Martin Brundle. However, his distinctive style is a major contributor to the enjoyment of watching F1 in the UK, and it is hard to imagine what it will be like when he is no longer involved.

He is passionate about motor racing, and, over-enthusiastic mistakes notwithstanding, has an awesome knowledge about the sport and its history. It is not unusual to hear him say during a race something like, "And that reminds me of a similar incident in 1964..." and then go on to recount the details!

In 2000, Murray missed a Grand Prix for the first time in his career due to a dislocated hip, and it may be that this has influenced his decision to retire. In 2001 he commentated on only 12 out of the 17 races, to give his successor, James Allan, a chance to settle in.

Murray has often said how much he loves Formula 1, even going so far as to say, "Cut me, and I will bleed Castrol-R!". His fondness for the sport and in particular the British driver Damon Hill was evident in 1996, as Damon won the World Championship. After a spectacular race an emotional Murray was heard to say, "I've got to stop now: I've got a lump in my throat."

1996 was also the year Formula 1 moved to ITV, and there was some debate about whether they would keep Murray on. However, in the event those in charge realised that F1 without Murray Walker is simply not F1 for many fans, and he retained his position. Murray Walker has been commentating on Formula 1 Motor Racing for 50 years.

Murray's style of commentating is unique. His high-pitch, high-speed delivery makes even the most routine of developments seem exciting. He is known for his tendency to get his words muddled at times of excitement, and there is a multitude of "murraywalkerisms" as a result.

It was an oblique tribute to Murray Walker's key role in the shaping of formula one's televised image over the past three decades that the Jaguar driver Eddie Irvine felt obliged to blurt out a dose of light-hearted, if hardly diplomatic, criticism of Bernie Ecclestone's grand prix show at Indianapolis at the weekend.

Invited to another Walker tribute party as the 77-year-old prepared to hang up his headphones after yesterday's US grand prix, Irvine made it clear that he thought the current formula one television show offered less than compelling viewing.

"At first his mistakes used to annoy me before I was old enough to realise it didn't matter," he said. "He lifts the whole thing".

"I tried once turning the sound off on one of Murray's broadcasts and God, Bernie, we don't put on a good show."

Irvine's effort at humour was interpreted either as an amusing slice of dissent from a man known for his trenchant remarks or a classic case of a highly paid sportsman biting the hand that feeds his £5m annual retainer.

However, he explained his comment away by saying that he had been trying to express just how crucial is the role of an informed and enthusiastic commentator - in this case Walker.

The Englishman's departure will leave a void which his successor - former pit-lane commentator James Allen - will find extremely difficult to fill.

"Murray made every race like losing your virginity", said David Coulthard. "It was always that exciting."

Throughout the Indianapolis weekend there was much backslapping and joshing with Walker, who is a genuinely popular man in the formula one fraternity. For his part, he seemed rather quiet and thoughtful, clearly realising that the end of his globetrotting road had finally arrived.

"What I will miss most is the sense of belonging to a community of friends who work and travel together in the formula one business", said Walker. "We're all in this business as competitors in many ways, but we're also bound together by a sense of common purpose and underlying friendship".

"But I don't think I will have too much spare time next year as I will spend much of the time travelling while promoting my autobiography."

Synopsis of Murray's book

Murray Walker is acknowledged worldwide as the voice of motor racing - and the man responsible for introducing millions of viewers to the previously inaccessible world of Formula 1. Here he tells the story of his incident-packed life. Murray Walker is seen as an institution in the sport.

When the man who made famous the catchphrase "Unless I'm very much mistaken... I AM very much mistaken!!!" announced that he was retiring as ITV's Grand Prix commentator at the end of the 2001 season, the media reacted as if the sport itself was losing one of its biggest stars. His reputation for mistakes enhanced his reputation. He was the fan who happened to be given the keys to the commentary box - and never wanted to give them back. His high-octane delivery kept viewers on the edge of their seats, while his passion for talking about the sport he loved was matched by an all-encompassing knowledge gained through hours of painstaking research before every race.