Murray Walker must be a nightmare to live with. At 87, the doyen of motorsport commentary has not slowed down at all. You can imagine him getting up in the morning: "And Walker's awake! He's first into the bathroom! Into the pits for some toast... No need for coffee, he's roaring to go!" And the drive to work must be unlike any other commute.

Murray Talker first commentated for the BBC at the age of 57, and one of the numerous fascinations of Murray Walker: Life in the Fast Lane (BBC2, Sunday) – a programme for which, naturally, he did the voiceover himself – was that he held down a job in advertising while pursuing his hobby at high speed on weekends.

He worked on the Mars campaigns and dreamt up the slogan for Pal dog food, "Prolongs Active Life" – he could hardly have coined a more appropriate description of his own existence. Perhaps his longevity is down to pet food after all. When he was selling Kitekat to shopkeepers, he would have a spoonful himself to prove to them how good it was. So if cats and dogs could talk, would they sound like Murray Walker?

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He cut his canines with scrambling. "This is proper motorsport for me," he breathes. "Muddy fields full of fanatics." The word "obsessed" crops up frequently, and his passion stems from his hero worship of his bike-racing father Graham. Dad was the lead commentator on the dirt bikes at the time, so perhaps uniquely in the history of British sport, father and son shared the microphone for 13 years until Graham's death.

It must have been quite a contrast, from working in tandem with your old man to riding pillion with the hopelessly flamboyant James Hunt. "I didn't admire things about his lifestyle," says Walker. But we can revel in the stories of Hunt trying to get a word in edgewise, once raising his fist to Walker's face only to find Walker squaring up to him while continuing his commentary, or Martin Brundle wrapping the microphone lead around Walker's neck and dragging him across the commentary box, Walker again carrying on the endless stream of words regardless.

It's a combination of sheer lunacy and consummate professionalism which is also a requirement of the sport he loves. But among the fast cars and pit girls and champagne, he also had to describe death on the track, often the killing of his friends such as Ayrton Senna. He was surely closer to the sportsmen he admired than any other media men and they still greet him with great warmth as Murray Stalker haunts the tracks.

Never was his affection for his subjects more in evidence than when Damon Hill won the World Championship, to which Walker reacted: "I've got to stop because I've got a lump in my throat." It was perhaps the only time he has been lost for words in 40 years. Like the men and machines he admires, it takes a lot to stop him.

* Walker is also celebrated for his on-air mistakes or "Murrayisms". So he may have smiled if he heard Test Match Special's Jonathan Agnew make an inadvertent tribute to one of the great cricket commentators and masters of accidental innuendo, Brian Johnston, when he talked about Kevin Pietersen changing his bat grip at Lord's: "It's not easy putting on a rubber, is it?" From Johnners to Johnnies, when it comes to live cock-ups there's very little protection.