Paul Burrell will today claim he would never have written his memoirs had he not been sidelined by the Royal Family after the death of Diana, Princess of Wales.
Mr Burrell's book, A Royal Duty, will go on sale today but Mr Burrell said he would have kept the correspondence secret if he had received "just one call" from Buckingham Palace.
In an interview with Fiona Bruce tonight on BBC 1's Real Story, the former butler said: "Just one telephone call would have stopped it, one. Is that too much to ask - really? Having served the Royal Family for 21 years, is one telephone call too much. It's not. They do live in the modern age, don't they?
"Never did I consider writing this book until the process took hold of me and squeezed me and made me someone different. The process being the Establishment, the Royal Family and everything."
He urged Princes William and Harry, who issued a statement condemning the book on Friday, to "grow up" and break free from the "grey men" in suits he claims are dictating their behaviour.
Mr Burrell's interview, which was recorded at his home in Cheshire, marks the start of an intensive publicity tour for the book as 135,000 copies go one sale in stores across Britain and a further one million are already on sale in the United States.
In a serialisation of his book, Mr Burrell made public a letter from Diana about a plot to kill her in a car crash and correspondence from the Duke of Edinburgh in which he and the Queen opposed the Prince of Wales's affair with Camilla Parker Bowles.
Critics claim the book is just a money-spinner for the former butler and a means of revenge against those who were responsible for putting him on his abortive trial last year for the theft of Diana's belongings.
Mr Burrell replied to the statement from the princes - in which they accused him of "cold and overt betrayal" - by saying: "We have to grow up and get on with it and the boys are now adults. They are not children any more and their mother will be talked about. She is an icon of the century.
"I felt immediately those boys were being manipulated and massaged by the system, by the palace, by the grey men in suits - whatever you want to call them. Too many people were busy spinning and William and Harry were sent out as the emotional cannons."
He said it was "interesting" that the statement was issued not from Buckingham Palace but from Clarence House - "the home of Camilla and Charles".
Mr Burrell, 45, who is expected to meet the princes for talks soon in an attempt to clear the air, even suggested the princes would benefit from a "chat" with his own sons, Alex, 18, and Nicholas, 16.
"I'd love to give them a piece of my mind. I'd like to say: 'Come and see my boys. Have a chat with them, see what they feel and think'."
Vivienne Parry, a friend of Diana, said Prince William should put the former butler "back in his pantry".
The former trustee of the Diana Memorial Fund, described Mr Burrell's book as a "cynical exploitation" that had been "in the making for a very long time".
"I think there has been no wrestling with his conscience, the only thing he has been wrestling with is which letter to draw from the capacious file marked 'P' for pension plan," she told the Breakfast With Frost programme yesterday.Reuse content