Former diplomat Sir Christopher Meyer has defended his memoirs, saying it is legitimate to reveal how politicians behave when abroad.
In his first interview since extracts were serialised in newspapers, Sir Christopher told the BBC he had to "ride out" the widespread criticism.
He said he had "absolutely no plans" to resign from the Press Complaints Commission, as critics have demanded.
Prime Minister Tony Blair was among politicians to come under his scrutiny.
Speaking on BBC One's Sunday AM, Sir Christopher said: "Politicians are elected officials.
"I think it is legitimate and reasonable to be able to describe in some detail how they perform their jobs when they go abroad."
He added: "What it shows is what complex characters and complex problems politicians have to face and above all Tony Blair comes out in all that complexity.
"I hope it is not a cartoon of him or anybody else."
The Cabinet Office had approved the manuscript for publication, after consulting the Foreign Office.
However, Foreign Secretary Jack Straw has been among senior officials to criticise its publication - a stance that has caused Sir Christopher some concern.
"[It was] cleared to be published - what exactly is going on here?
"I write a book, I made a judgement between what I think is right to keep confidential and what it is right to bring out into the public gaze.
"It goes into the Cabinet Office, it pops out a couple of weeks later, and I am told they wish to make no changes to the text and then we publish."
Spew of books
He said he did not know what he would have done if changes had been made, but "my instinct is publish and be damned because I think there are areas of activity in foreign policy and government where it is right to shine a light".
He said there had been a "spew" of books from former and serving ministers as well as special advisors about their time in the current government - and that the civil service was at a "disadvantage" when it came to doing the same thing.
The memoirs, DC Confidential, covered Sir Christopher's time in Washington and London, as John Major's press spokesman.
He said he did not like disagreeing with friends and former colleagues, but said "you just have to take it".
"I knew that what I had written would not go down well with everybody, so you expect to be criticised and you just have to ride it out."
Sir Christopher is due to be questioned on the issue next month by the Commons public administration select committee.
He said if there were any complaints to the Press Complaints Commission, of which he is chairman, about the serialisation, or anything else attributed to himself, then he would withdraw from the investigation.
Criticism in the book included Mr Blair's handling of the run-up to war in Iraq, saying that a six-month delay to prepare for a post-Saddam Hussein Iraq would have been better.
Sir Christopher said: "It would have given us more time to put in place the kind of mechanisms, alliances, arrangements that might have avoided all that bloodshed that we have had to suffer since then."