Former UK Prime Minister Boris Johnson has claimed the late Queen Elizabeth II had bone cancer in her later years.

In a chapter from his upcoming memoir Unleashed, Johnson recalls his final meeting with the monarch at Balmoral on September 6, 2022, two days before her death, claiming staffers tried to warn him her condition had deteriorated.

“I had known for a year or more that she had a form of bone cancer, and her doctors were worried that at any time she could enter a sharp decline,” he writes in an extract published by the Daily Mail UK.

Boris Johnson, here pictured with the Queen welcoming him as leader in 2019, has reflected on the last time he saw the monarch. Photo / Getty Images

He described her as pale and “stooped” with noticeable bruising on her hands, “probably from drips or injections”, adding the Queen still smiled throughout their conversation.

“To go to see the Queen, for an hour a week, and to pour out your heart was more than a privilege. It was a balm, a form of free psychotherapy. It was like being at school and being taken out to tea by a much-loved grandmother.”

Her parting words of advice to him were, he says, “There’s no point in bitterness”.

Queen Elizabeth died on September 8, 2022. Photo / Getty Images

The late monarch’s death certificate confirmed her official cause of death was “old age”, rather than any particular illness.

Part of the certificate was released in September 2022, revealing she died at 3.10pm on September 8 at Balmoral Castle in Scotland. Her daughter Princess Anne was by her side when she died.

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Anne and her brother King Charles, who arrived in Balmoral at 10.30am, were the only family members who got to say goodbye to her, with a flight carrying Prince William, Prince Andrew, Prince Edward and Sophie, Countess of Wessex, delayed.

The late monarch was farewelled with 10 days of mourning, including her lying in state in Edinburgh and London and her state funeral. She was laid to rest in Windsor alongside her husband Prince Philip at St George’s Chapel.