Roy Keane has suggested that he will never repair his relationship with former Manchester United manager Sir Alex Ferguson.

The Irishman has been critical of Ferguson in his new autobiography The Second Half, which he officially launched at the Aviva Stadium in Dublin this afternoon.

Keane publicly hit back at Ferguson after he was criticised in the Scotsman's book, which was released last year, and the ex-United captain has slammed his former boss once again by claiming that he was wrong to talk badly of the players who helped him bring success to Old Trafford.

When asked in today's press conference if he would ever forgive Ferguson, Keane said: "Good question. Not sure. Football's a small world and eventually you think you might cross paths again.

"The problem I had, when you're writing and reflecting on something - we had our disagreement - but it's afterwards when people start coming out with all sorts of nonsense. We had a great team that entertained a lot of people. So to criticise people like that, not just me, people who brought him a lot of success, I thought it was wrong."

Keane has rejoined the Republic of Ireland setup as Martin O'Neill's assistant boss for Saturday's Euro 2016 qualifier against Gibraltar.