Alex Ferguson never considered Jose Mourinho to potentially succeed him at Manchester United because he knew of the Portuguese manager's desire to return to Chelsea.

Mourinho left Real Madrid and started his second stint at Chelsea when he signed a four-year deal in June 2013.

That came just a month after Ferguson had announced he would retire, with David Moyes replacing him at United.

But Mourinho said the Scot knew of his want to return to Stamford Bridge, meaning he was never considered for the United job.

"Every manager in the world looks at Man United as a huge club but I wanted to come to Chelsea," he said during an interview for a BBC documentary.

"And we didn't bring that to the table because we were so open and he knows so much about myself that he knew that for almost a season, I want to leave Real Madrid and I want to come to Chelsea."

Such was the relationship between Mourinho and Ferguson, the former claims the 73-year-old told him of his decision to retire months before the news was public.

Mourinho said he was worried the information would come out.

"He told me a huge secret, not many people knew, like, one month or two months before the decision," he said.

"I know that he trusts me, because if he doesn't, he doesn't tell me but I was scared.

"I was scared so when finally he informed the media about this decision it was a sense of relief."