Sir Jackie Stewart is relieved Michael Schumacher is retiring from Formula 1, as he believes the German risked his reputation by carrying on.

Schumacher, who quit in 2006 before returning with Mercedes four years later, has announced he will retire at the end of the season.

"His reputation has already been affected by his unsuccessful return to the sport," Stewart told BBC Sport.

"People will applaud the decision as it should have happened a while ago."

He added: "The speculation within the whole F1 community has been that Michael should be retiring - and hopefully not for a short period this time.

Schumacher crashed into Vergne in Singapore

"In a way I am sorry Michael came back. Recently he's had too many incidents."

Stewart - who won Formula 1 world titles in 1969, 1971 and 1973 - said he had been particularly alarmed by Schumacher's collisions with Williams driver Bruno Senna at the Spanish Grand Prix and Toro Rosso's Jean-Eric Vergne in Singapore.

"These two incidents, running up behind other drivers and hitting them at great speed, you might have expected from an inexperienced driver in their first year, but not from one of the great drivers," Stewart said.

"These driver errors would just never have happened with the likes of Alain Prost, Ayrton Senna, Niki Lauda or Jim Clark. They could have ended in tears.

"There comes a time when everyone recognises it may be time to retire."

quote He's one of the greatest drivers of all time, although it's not possible to say he's the greatest Sir Jackie Stewart

Stewart, 73, hopes Schumacher can now find something to replace the excitement and stimulation of driving an F1 car.

"I hope there will be a place for him within the sport that will consume him, without having to drive cars," the Scot added.

"What I would not like to see him do is German touring car racing, DTM, or another form of motor sport.

"I think he needs to remove himself from participation behind the wheel in a complete way. He retired before, but obviously missed the sport hugely and there wasn't anything in his life to stimulate him in the way F1 racing had done."

The Scot says Schumacher, 43, should not be short of job offers, although he believes it could be difficult to find a prominent role with Mercedes.

"Michael is a very marketable individual," Stewart said. "The name Michael Schumacher is globally recognised, he is fluent in more than one language and his record as a driver is above all others.

SIR JACKIE STEWART Nickname: The Flying Scot

F1 races: 99

Wins: 27

Stewart Grand Prix: Team principle. One GP win (at Nurburgring 1999)

Knighted: 2001

"The most obvious thing would be for him to work with Mercedes or Ferrari, although with Niki Lauda at Mercedes [as non-executive chairman] I'm not sure they could cope with two retired world champions.

"Saying all that, he's rich enough to buy into a F1 team or even become a full owner."

Although Schumacher is the most successful driver in the history of F1, with seven world titles and 91 race wins in a career spanning 19 seasons, Stewart argues he is not the greatest.

"His record will, I think, remain unbroken forever," Stewart, who ran the Stewart Grand Prix F1 team from 1996 to 1999, said.

"He's one of the greatest drivers of all time, although it's not possible to say he's the greatest.

"The number of Grand Prix he's driven are considerably more than anyone else. Juan Manuel Fangio didn't come to Europe to race until he was 39, yet won five world championships. His ratio of wins to races was extraordinarily good.

"Jim Clark likewise. Myself, I only raced in 99 Grand Prix races but won 27. Although that's nothing like the 91 that Michael has won, the average was good.

"Michael's record in F1, particularly his Ferrari period, was so dominant because the car and engine was unquestionably the best on the grid and there was no doubt about who was number one and got most attention in the team."