However, I challenge anyone to read his full story, which I ghostwrote, and not understand and respect his decision to tell it.
Actually, the idea for the book was mine, not his, though he didn't take much persuasion. And let's get one thing straight: neither of us did it for the money. Indeed, for differing reasons, both of us were prepared to write the book for nothing. Until it was finished, we didn't even know if we would cover our costs.
The project began after I met Peter to interview him for a newspaper article in May last year. It was the day after the Crown Prosecution Service announced that he would not face charges, and after 18 months of forced silence, he was finally free to speak.
He poured out his heart about the way he had been treated by the Labour leadership, and the hugely damaging price he had paid for what he felt was a collective mistake.
He seemed more hurt than angry or embittered and was clearly desperate to set the record straight. He had so much to say that, there and then, I floated the idea of working on a book together.
Neither of us knew quite what we were getting into but, every time we met, he told me things I found funny, interesting or extraordinary -- sometimes all three. He was frank and self-deprecating, and the more we talked, the more confident I became that his story would interest others as much as it interested me.
I am not a big fan of heavy political books, and it was the sense that he had a compelling human-interest story as well as serious information that appealed to me. He spoke very movingly about the death of his father, his marriage and his role as a foster parent, and was very open about his feelings.
Timing was obviously a big issue. Peter was already sticking his neck out by revealing sensitive information and knew that publishing before the election would cause further anger. But there seemed little point in bringing out the book after everyone had lost interest. In any case, those who argue that he should have waited until after the election are in effect saying the public should be told about Gordon Brown's regime only after it is too late for them to do anything about it.
This seems a cowardly and dishonest way to treat the electorate.
It is easy for critics to carp about Peter's disloyalty, but I wonder how many of them would feel an iota of loyalty in his shoes? Make no mistake: this man almost lost everything, arguably through little fault of his own.
Expecting him to keep quiet about it, to spare the blushes of those who hung him out to dry, is a demand too far.
Isabel Oakeshott is deputy political editor of the Sunday Times