Franck Ribery was at Marseille when Ferguson showed brief interest in him

Sir Alex Ferguson rejected the chance to sign Bayern Munich star Franck Ribery for Manchester United back in 2006 after watching him for only 45 minutes.

The revelation is one of a number to be made in the latest set of diaries published by Tony Blair's former communications chief Alastair Campbell, a close friend of the former Old Trafford chief.

According to The Sunday Times, Campbell was with the United boss when Ribery, then playing for Marseille, faced Bolton Wanderers in the UEFA Cup in February 2006.

But Ferguson did not take too long to make his mind up about the France international, then 22, and about to be named Ligue 1's Young Player of the Year.

Ribery has gone on to enjoy great success in Germany with Bayern Munich

Campbell wrote: "Alex was watching Franck Ribery, the Marseille winger, but decided by half-time he was not good enough for United."

Ribery would have one more season with Marseille and in June 2007 he secured a move to Munich, after also being heavily linked with Arsenal.

Since then, Ribery has gone on to win seven Bundesliga titles with Bayern and he was part of their Champions League-winning team at the end of the 2012-13 season.

The diaries also include further revelations about Ferguson's tempestuous relationship with Roy Keane.

Roy Keane had demons, according to Sir Alex

Ferguson savaged the former United captain in his own autobiography and Campbell wrote: "He [Ferguson] felt Keane had what it took in so many ways but he had demons and they would come out.

"He was actually someone who didn't like people that much unless they met his own standards.

"I said you used to say he was the most intelligent player you'd had and the one likeliest to be a top manager. He went 'Wrong. There is something not right there.'"