England coach Andy Flower has slammed off-spinner Graeme Swann for criticizing star batsman Kevin Pietersen in his autobiography, 'The Breaks Are Off, My Autobiography'.

Swann has criticized Pietersen's captaincy stint, saying that he was a bad choice to lead England in 2008 and 2009.

Flower, however, said that Swann should have waited till retirement before writing such a book.

"I personally disagree with current players making comments about their team-mates. My personal opinion is that it is not the right thing to do," the Daily Mirror quoted Flower, as saying.

"I don't think the commercial opportunities are that important to be honest. However, I think Pietersen has handled it very well and he and Swann get on fine. I think he has handled it very maturely and there aren't any issues arising from it," he added.