Manchester United manager Sir Alex Ferguson feels he has another two or three years left in the job but would only retire on the back of a success.

The 70-year-old Scot had been due to step down a decade ago but has justified his change of heart by winning five more Premier League titles to complement the seven he already had and adding a second Champions League triumph. He has also won the FA Cup and three League Cups during that time.

Ferguson said: "I think you always want to go out on a winning note. Hopefully we can do that. I don't know how long I can last now but if my health stays up I don't think another two or three years would harm me any."

And, while he insists there is no other role for him directly involved in football after he leaves his Old Trafford post, he has no plans to fade into the background.

"I would definitely finish - but I would remain active," he added.

"I think there would be a role at United after I finish."

In a lengthy interview with Radio 5, extracts of which have been published on the BBC Sport website, Ferguson reflects on many aspects of his life and career.

The United boss revealed he missed out on the chance to sign Joe Hart, leading the way in clean sheets this season for title rivals and near-neighbours Manchester City and now England's first-choice goalkeeper.

And he believes the 24-year-old is set to enjoy a lengthy spell as the national team's number one.

"I could have bought Joe Hart for £100,000 so we all make mistakes," he admitted. "I've no doubt [Hart will be England goalkeeper for the next 10 years]. If you look at the England goalkeeper situation for the last 20 years, I would think he's easily the best."