By Ed King

Mansell is the man to watch - he's very fit and tremendously talented Murray Walker

Retirement suits some people, but not it would seem Murray Walker, the undisputed doyen of motorsport commentators.

His last race was the 2001 US Grand Prix, but the mouth muscles have been twitching, and despite swearing never to get back in the box, that is exactly where he will be this weekend.

The inaugural Grand Prix Masters race roars into life on Sunday, with a collection of former F1 greats rolling back the years at Kyalami in South Africa.

And when the lights change from red to green a familiar voice will be heard above the rumble of the engines - and viewers will know Walker is back - Go! Go! Go!

"I had vowed in 2001 after 53 years commentating to stop but when the GP Masters approached me I was enormously tempted," Walker told BBC Sport.

"I've missed the buzz of F1 enormously, in particular the friendship and the camaraderie and to be honest it's great to be back."

Grand Prix Masters Sunday, BBC Two, 1600 Coming up on Grandstand

Masters events have sprung up in tennis, golf and to an extent football and rugby union, but perhaps because of the risks involved no-one had previously considered one for motorsport.

That changes with the arrival of the GP Masters, boasting among others former Formula One champions Nigel Mansell, Emerson Fittipaldi and Alain Prost.

All the drivers have had to undergo stringent fitness tests, and Walker believes that despite the veterans' ages the quality of racing will be undiminished.

"They say 'if you've got it you never lose it' and I think that applies to the drivers taking part," Walker said.

"They may be a bit rusty but they'll soon get rid of that, and I think people will be impressed by the speeds the cars hit.

"The only thing that might be called into question is their stamina; it's pretty hot in South Africa and we're at quite a high altitude, and that could be a factor."

What will not determine the winner is the make of the car; they are all single-seater race cars powered by V8 Nicholson-Cosworth engines, generating 650 brake horse-power.

GP MASTERS: THE NUTS & BOLTS Car: Single-seater race car Engine: V8 Nicholson-Cosworth BHP: 650 Torque: 320lb ft at 7,800rpm Top speed: 200mph Minimum age: 45 Prize fund (race 1): $500,000 Top drivers: Nigel Mansell, Ricardo Patrese, Alain Prost, Emerson Fittipaldi, Ren� Arnoux, Andrea de Cesaris

With a top speed of 200mph these are fast machines, and without driving aids such as traction control that are found in Formula One, they will test the drivers' abilities to the full.

The man Walker is most looking forward to watching again is Nigel Mansell, who he counts as a friend and also one of the greatest drivers from this island.

"You've got to say that Mansell is the man to watch - he's very fit and tremendously talented," he said.

"No-one has ever had a hold on the British public like Mansell had and still has; Nigel is a man of the people, a showman, and I think he will do very well on Sunday.

"The other man I will be watching closely is one of the oldest out there, Emerson Fittipaldi, the 1972 and 1974 Formula One champion from Brazil.

"He's 58 but at Silverstone he was one of the quickest out there - smooth, impressive and came in with a grin like the Cheshire Cat, so I think he could challenge too."

Age can be deceptive, and once these grand masters have donned their overalls and helmets there will be no telling how old the man behind the wheel is.

And all the back-slapping, smiling and cheerful banter does nothing to hide the fact that every one of these men is desperate to prove that they have lost none of their edge.

"When the lights go green the red mist will descend and they'll all have that chequered flag on their mind - it should be a great spectacle," Walker said.