An unauthorised biography on Prince Charles is set to lift the lid on household secrets.

Prince Charles

Prince Charles

Author Tom Bower is publishing a new tome about the first in line to the throne this March, and has claimed he has spoken to over 120 personnel as research for the book, which he claims allowed him to be "welcomed into the inner sanctum of Clarence House".

And he claims readers will get an inside look at "a royal household rife with intrigue and misconduct".

According to the Daily Mirror newspaper, Bower said: "There are a lot of revelations. I was amazed how much new material there was. It's got a lot of very, very new, untold information."

However, despite his bold claims about the content of the book, insiders are said to be "very sceptical" as to whether Bower got such access.

One said: "Nobody on this side of the fence believes 120 people have spoken to him."

A spokesperson for the palace commented on the fact they weren't able to offer Bower a place to cover a day of the 69-year-old royal's tour of Wales last July, which saw him given a guided tour of Royal Mint's HQ in Glamorgan, South Wales.

A source claimed: "Bower asked permission in advance, but about two days before, they said it was full. Bower couldn't believe they didn't have space for one person behind a rope."

But the palace said: "Bower was offered alternative engagements to visit - owing to there not being a space on that one occasion - which he declined."

The book is set to document "Charles' politics and his attitude towards his family" and how HRH - who is married to Camilla, Duchess of Cornwall - changed following the death of his ex-wife Princess Diana in 1997.

An insider concluded: "Until now all the books about Charles have been pretty reverential. They have all sought to get his approval. This treats him as a story, not as an object to be glorified."