Prince Harry threatens the Royal Family with an explosive tell-all attack.

Prince Harry's memoir, due out in May, has the potential to rock the Firm with its 'dual attacks'.

Robert Lacey, a royal commentator and expert, has issued this warning.

The memoir of Prince Harry is being ghostwritten in English by JR Moehringer, a journalist and novelist.

JR Moehringer is well-known for writing the autobiography about former tennis star Andre Agassi.

Mr Lacey cautioned that Prince Harry's memoir contains a "powerful, exploratory" promise.

"One would expect a book that sets new standards for royal analysis.

"I hope [Moehringer] will also be looking at the institution.

Agassi was not only destroyed by him, but also his parenting and upbringing.

"Therefore, one would expect the same kind of dual attack in his writings about Harry and the monarchy."