A former presidential doctor has accused Joe Biden’s White House physician of lying or being incompetent after the 82 year-old was diagnosed with advanced prostate cancer last week.

Ronny Jackson, who treated Barack Obama and also Donald Trump during his first term, is now a hardline Republican congressman.

He echoed questions among allies of Mr Trump about whether those in Mr Biden’s circle knew more than they were letting on about his health.

“I think there’s a probability here that they knew he [Biden] had prostate cancer some time ago and just didn’t tell the American people,” he told the Washington Free Beacon, a conservative news site.

He singled out Mr Biden’s doctor of more than 15 years for either missing the diagnosis or hiding it.

“Dr Kevin O’Connor either lied to the American people or he’s incompetent,” Dr Jackson said, adding that he had tested both Mr Obama and Mr Trump.

He also said he feared Mr Biden had between 12 and 18 months to live following the diagnosis, but added that it was not his area of medical expertise.

Dr O’Connor has become the focus of anger in Maga circles following the announcement by Mr Biden’s office on Sunday that he had been diagnosed with an aggressive form of stage-four cancer.