Prince Harry has denied he gave Prince Andrew “a bloody nose” during a fight at a family gathering in 2013.

According to an excerpt from a new biography of the disgraced Duke of York, published in the Daily Mail on Saturday, the pair had a heated argument that escalated into a physical altercation. “Punches were thrown over something Andrew said behind Harry’s back”, the author Andrew Lownie claimed.

The alleged fight began when “Harry told [his uncle] he was a coward not to say it to his face. Harry got the better of Andrew by all accounts, leaving him with a bloody nose before the fight was broken up.”

Lownie’s biography, Entitled: The Rise and Fall of the House of York, also claims Andrew told his nephew that his marriage to Meghan Markle, now the Duchess of Sussex, would “not last more than a month”.

He allegedly “accused Meghan of being an opportunist and thought she was too old for Harry, adding that his nephew was making the biggest mistake ever,” and told his nephew he had gone “bonkers”, accusing him of not doing “any due diligence into her past” before they got engaged in 2017.

Late on Saturday, a spokesperson for Harry and Meghan said: “I can confirm Prince Harry and Prince Andrew have never had a physical fight, nor did Prince Andrew ever make the comments he is alleged to have made about the Duchess of Sussex to Prince Harry.”

The duke and duchess have sent a legal letter to the Daily Mail over the publication of what their spokesperson described as “gross inaccuracies, damaging and defamatory remarks”.

The Guardian has approached Buckingham Palace and representatives for the Duke of York for comment.

Prince Andrew fell from grace after a disastrous Newsnight interview in 2019 about his friendship with Jeffrey Epstein, the late American financier and convicted sex offender. The duke was stripped of his royal and military titles in 2021.

The book claims Harry and his brother, William, had “problematic” relationships with Andrew for years and that Andrew was also rude about William’s wife, Catherine, the Princess of Wales.

King Charles has allowed his younger brother to stay in the Royal Lodge, a 30-room mansion in Windsor Great Park owned by the crown estate. However, last year the king ended Andrew’s allowance, estimated at £1m annually, raising questions about future arrangements.

The source quoted in Lownie’s biography claims the Prince of Wales is keen to “evict” the duke and his ex-wife, Sarah Ferguson, who lives with Andrew though the couple divorced in 1996.

According to Entitled’s source, “[William] also loathes Sarah … and can’t wait for the day when his father throws them both out. If Charles doesn’t, I guarantee you the first thing William does when he becomes king is to get them evicted.”

Harry broke ties with his family citing the “toxicity” of royal life and alleged racism towards his wife, moving with his young family to Canada and then the US in 2020. In 2022 he published a memoir, Spare, in which he detailed strains in his relationships with his father and brother.

Earlier this year he told the BBC he had forgiven his family and would “love a reconciliation”.