The crisis facing the royal family over the Epstein files revelations about Andrew Mountbatten-Windsor is more serious than the abdication of Edward VIII, the author of the former prince’s biography has claimed.

Andrew Lownie, author of Entitled: The Rise and Fall of the House of York, said that Mountbatten-Windsor’s actions had caused greater public anger than the abdication crisis, when the king stepped down from his role to marry the American divorcee Wallis Simpson.

Speaking at Oxford Literary Festival, Lownie said the abdication had been a “three-day wonder”, the full details of which the general public did not engage with at the time. He also said that Edward’s support of the Nazi party had yet to become common knowledge.

While Edward resigned voluntarily from his role to marry the woman he loved, Andrew had to be stripped of his HRH title and military honours after allegations about his continued relationship with the billionaire paedophile Jeffrey Epstein re-emerged.

Lownie said the late Queen had “crossed the line” legally “a lot” when she made allowances for Andrew, who it is thought was her favourite child.

King Charles III and Prince Andrew attending a funeral service.King Charles was “running the show” for the last few years of Queen Elizabeth’s life, Lownie said. He said that the late queen had made allowances for Andrew Mountbatten-Windsor, who, it is thought, was her favourite childADRIAN DENNIS/AFP

“By the end of her life, what people don’t realise, is that she was completely gaga. He [Andrew] would go up there and he would bully her into doing things. So for the last few years of her life Charles actually was running the show, rather than the Queen,” he said.

“There were MI6 officers who went to [royal] private secretaries and said, ‘Look he’s been caught with $5 million in a suitcase in Kazakhstan’, and they were sent away with a flea in their ear. The heads of the foreign office went and complained.

“He was made a vice-admiral in the navy, and that was after these allegations. She [the Queen] entertained a lot of these people. President Aliyev of Azerbaijan gave her a horse and she was thrilled.

“She, I’m afraid, abetted this. The whole family abetted this — they knew about it,” he said.

He added that people in royal circles had been talking about the allegations since 2011.

Anti-monarchy activists hold signs spelling "WHAT DID YOU KNOW?" and a banner reading "ABOLISH THE MONARCHY CHARLES, WHAT ARE YOU HIDING?"Activists from the anti-monarchy group Republic demonstrate outside Westminster Abbey on Commonwealth DayVUC VALCIC/Alamy

“Charles is in a difficult position. He didn’t realise these Epstein files would be released — they thought they’d got away with it.

“Now they’re caught. They’ve got all this stuff in black and white there. On one hand, they’re saying publicly ‘Of course we’ll help any inquiry’, but I know they are putting pressure on police protection officers to not go beyond their obligations on confidentiality, people on UKTI [UK Trade & Investment, for which Andrew was an envoy] have been reminded about their pensions.”

Lownie, who is working on a biography of Prince Philip, said he thought that Andrew should be charged with treason, rather than misconduct in public office. “He gave away confidential information to other countries. Also, there is insider trading there.”

He said he thought it was unlikely that Andrew would be prosecuted. “They [Buckingham Palace] don’t want Andrew turning up in court saying everyone knew about this — why am I being penalised?”

Entitled: the Rise and Fall of the House of York has become a Sunday Times bestseller and is published by William Collins, an imprint of HarperCollins. The paperback version is out in May.