Tesco has launched an investigation after one of its stores started selling copies of Roy Keane's autobiography three days early.

The former Manchester United captain's book, which contains details of a drink-fuelled fight with ex-United goalkeeper Peter Schmeichel, is due for official release on Thursday.

It was put out on the shelves of the Burnage store in Manchester this morning.

Titled The Second Half, it was co-written by author Roddy Doyle.