Former British prime minister Tony Blair is “extremely concerned” over the impact his wife’s upcoming book will have on his relationship with his successor Gordon Brown, The Sunday Telegraph reported.Cherie Blair’s publisher said earlier this month that she had struck a deal to publish “a warm, intimate and often very funny portrait of a family living in extraordinary circumstances.” Citing a friend of the ex-prime minister, though, the Sunday Telegraph reported that Tony Blair was concerned over the impact the book, set to hit shelves in about a year, would have on his improving relationship with Prime Minister Brown. “Tony is extremely concerned about the book,” the Telegraph’s unnamed source was quoted as saying. “He is getting on really well with Gordon at the moment and the last thing he wants is for damaging revelations to wreck things again. He can’t stop Cherie from writing it, though.” Blair and Brown have had an often divisive relationship in their 10 years together in power, when Brown was finance minister, and tensions were often close to the surface. Cherie Blair is said to have disliked Brown and at last year’s Labour Party conference was alleged to have dismissed as a “lie” that her husband and his number two had a close working relationship.