Prince William's allies hit out at 'outrageous' suggestions he briefed against Prince Harry following claims by 'Meghan's mouthpiece' Omid Scobie

Friends of the Prince of Wales last night blasted 'outrageous' suggestions that he briefed against his own brother after the latest round of claims by the writer dubbed 'Meghan's mouthpiece'.

Supporters leapt to the defence of the future king, expressing their anger and frustration that Omid Scobie was 'peddling' what they described as conspiracy theories 'dressed up as fact' ahead of the publication of his new book tomorrow.

In extracts from Endgame, his second book attacking the Royal Family – as well as interviews to publicise it – Scobie has suggested that William 'prioritised his loyalty to the monarchy' over his brother and actively leaked information about Harry and Meghan to undermine them.

Kensington Palace has remained silent on the furore, but the frustration of those loyal to William was clear. One told the Mail that Scobie's depiction of the heir to the throne was the 'very opposite' of William's personal mantra.

'He has always been very tight-lipped when it comes to his family and made clear to anyone within his orbit that he would not do 'deals' with the media,' they said.

'Like Harry, he is scarred by his childhood experiences, seeing his mother and father engaged in what was dubbed 'the war of the Waleses'. He never wanted history to repeat itself.

'That was something that he and Harry were meant to be united on.'

Another added: 'It's one thing writing a critique of the Royal Family. That's freedom of expression. But it's another thing to peddle conspiracy theories dressed up as fact. The suggestion that [royal aides] were briefing negative stories [about Harry and Meghan] is totally fabricated. It just didn't happen.

'The truth is that everyone was walking on eggshells practically from the engagement trying to keep them happy.'

In his latest interview, with The Sunday Times, Scobie breathlessly describes William as a hot-headed, power-hungry man who has become increasingly willing to allow the Palace to deploy dirty tricks. Aside from the prince occasionally being prone to the famous Windsor temper, those who know him well say it would be anathma to him.

The author also paints the Princess of Wales as an under-achiever, who is too scared of putting a foot wrong to stick her head above the parapet.

'That will really wind William up,' said another source.

'He's immensely proud of what his wife has achieved. The princess has been the driving force behind a great deal of their work, particularly when it comes to bettering mental health.'

Insiders also maintain that a number of significant claims made by Scobie are 'just plain wrong' and 'rehashed'.

In response to an accusation that King Charles is out of touch and demands his shoelaces are ironed, one source says flatly: 'That was total bull**** when it first surfaced 20 years ago, and still is now.'

Scobie also raises issues about racism and diversity within Charles's household. He now accuses two people in royal circles of expressing concern about Prince Archie's skin colour, but claims libel laws prevent him from naming them.

Questions also remain about the sourcing of huge swathes of the book.

Harry and Meghan have moved to distance themselves from it and Scobie has claimed he is not part of the 'Sussex camp', despite a wealth of intimate detail about letters, phone calls, text messages and conversations between themselves and other members of the Royal Family.

Meghan has previously been forced to apologise for misleading the High Court for failing to remember emails she had exchanged with an aide to help Scobie with his previous Sussex-friendly book, Finding Freedom, after earlier stating she had no dealings with it.

In Endgame, Scobie openly details private conversations he had with multiple members of their staff. And he even boasts about a short phone call he had with Meghan herself after she married Harry.

Scobie, clearly angry about the coverage of his book in recent days, ranted on social media that the 'twisting of facts and misquoting going on right now has reached new levels of desperation'.

Buckingham Palace declined to comment last night.