Scotland Yard is considering suing Princess Diana's former police bodyguard in a bid to stop him cashing in on revelations about her private life.
Former protection officer Ken Wharfe's decision to publish details of his six years at Diana's side in a book has enraged old colleagues.
Police chiefs have condemned him and are looking at "all options" open to them, which could include legal action.
Senior officers and lawyers are known to have looked at the case of Peter Topping, the detective who led the search for some of the victims of the Moors Murders.
An action against him by Greater Manchester Police Authority could be argued to have set a successful precedent against former police officers using confidential material from their professional careers for personal profit.
The authority made a claim against Mr Topping for breach of copyright and confidentiality after he published a book in 1989 which gave an account of interviews with Ian Brady and Myra Hindley. An out-of-court settlement was reached and part of the profits were paid to the authority.
Any successful action against Mr Wharfe could see him lose out on profits and have his book pulped.
The Royal Family, particularly Princes William and Harry, have been angered by his publication of Diana: Closely Guarded Secret and the Prince of Wales's private secretary Sir Michael Peat is being kept informed of Scotland Yard's intentions.
Although he would have signed the Official Secrets Act, that does not prevent Mr Wharfe publishing details about Diana which do not jeopardise state security.
Wharfe has repeatedly insisted his book is intended to tell the truth about Diana and prevent her memory being airbrushed from history.