The Prince of Wales had just 20 minutes notice of his son’s plans to confirm his relationship with Meghan, according to a new book on the couple.

Clarence House was said to be “crushed” as the confirmation of the rumours dominated the news cycle and took the limelight away from Charles and Camilla’s diplomatic tour of the Gulf.

In Finding Freedom, serialised by the Times and the Sunday Times, Carolyn Durand and Omid Scobie wrote that Harry felt a need to “prioritise” Meghan over his duty to the greater royal family in the statement which hit out at the “racial undertones” of some coverage.

According to the co-authors, Charles was “disappointed” with the timing of the announcement but understood that a “tipping point” had been reached with Harry’s relationship with Meghan.

The statement was issued by the then Prince Harry’s Communications Secretary on November 8 2016, as Charles arrived in Bahrain – which his team had hoped would be “covered significantly”.

The book said: “A statement from Kensington Palace condemning the Press and, in the same breath, confirming Harry’s new girlfriend would all but eliminate coverage of Prince Charles’s tour of the Gulf.

“The Palace decided to go ahead with the statement nonetheless, much of which was drafted by Harry himself.

“Charles learnt of it just 20 minutes before it went out. Sure enough, as soon as Harry put out his declaration, the statement dominated the news cycle.

“The team at Clarence House, which had spent months putting together Prince Charles’s tour in the hopes that it would be covered significantly, was crushed.”

Extracts from the book, due to be published by HQ on August 11, have also covered claims the Duke of Sussex was angered by what he perceived as his brother’s “snobbish” attitude to his bride, and suggestions the Sussexes felt their complaints were not taken seriously and believed other royal households were leaking stories about them to the press.

Harry confirmed he was dating US actress Meghan Markle in the November 2016 statement and lashed out at the “wave of abuse and harassment” she has faced from the media.

In a lengthy and strongly-worded statement, Harry’s Communications Secretary Jason Knauf outlined the difficulties Miss Markle had experienced since news of their relationship broke.

Mr Knauf said “The past week has seen a line crossed. His girlfriend, Meghan Markle, has been subject to a wave of abuse and harassment.”

He added: “Prince Harry is worried about Ms Markle’s safety and is deeply disappointed that he has not been able to protect her.”

It was the first official confirmation from Kensington Palace that the pair were dating.

News of the royal romance emerged around a week before the statement was issued, with The Sunday Express reporting the pair met in May while Harry was in Canada promoting Invictus Games 2017, the paralympics-style competition for injured servicemen and women and veterans he founded.