Joe Biden forgot when he had served as vice president and could not remember when his son had died, federal prosecutors have revealed, as they warned of “significant limitations” in his memory.

Lawyers who interviewed Mr Biden in October found he had “hazy” recollections of his time in office under President Obama, and struggled to remember key details.

The Department of Justice’s special counsel Robert Hur published a report on Thursday into the storage of classified documents in Mr Biden’s garage.

The report concluded that the president should not be prosecuted over an apparent security breach, but warned that his memory had faded.

“He did not remember when he was vice president, forgetting on the first day of the interview when his term ended, and forgetting on the second day of the interview when his term began,” Mr Hur wrote.

“He did not remember, even within several years, when his son Beau died. And his memory appeared hazy when describing the Afghanistan debate that was once so important to him.

“Among other things, he mistakenly said he ‘had a real difference’ of opinion with General Karl Eikenberry, when, in fact Eikenberry was an ally whom Mr. Biden cited approvingly in his Thanksgiving memo to President Obama.”

A jury would find him an ‘elderly man with a poor memory’

The report revealed that Mr Biden asked the lawyers interviewing him: “If it was 2013 - when did I stop being vice president?”. He also asked: “In 2009, am I still vice president?”

Mr Hur, who concluded that Mr Biden had inappropriately stored classified documents, said that he may not have been aware at the time and that if he faced trial, a jury would find him to be a “well-meaning, elderly man with a poor memory”.

Mr Biden said he was “pleased to see they reached the conclusion I believed all along they would reach – that there would be no charges brought in this case and the matter is now closed”.

However, the report follows a series of incidents that have raised concerns about Mr Biden’s cognitive abilities, including two speeches in the last week where he claimed to have spoken to former world leaders who were dead at the time.

Speaking at two fundraisers in New York, the US president told the same anecdote in which he referred to speaking to Helmut Kohl and Francois Mitterand at a G7 summit in Cornwall in 20221.

Mr Kohl died in 2017 and had not been the country’s leader since 1998.

“When I first got elected president, I went to a G7 meeting with the seven heads of state in Europe and Great Britain,” Mr Biden said, as reported by the White House pool.

“I sat down and I said, ‘Well, America’s back’. And the president of France looked at me and said, ‘For how long?’ I never thought of it this way.

“Then Helmut Kohl of Germany looked at me and said, ‘What would you say Mr. President, if you picked up the London Times tomorrow morning and learned that 1,000 people had broken down… the doors of the British Parliament and killed some [people] on the way in [to] deny the prime minister to take office.”

Mr Kohl, who stood down more than 20 years ago, was not alive when the US Capitol was stormed by supporters of Donald Trump. He died in 2017 – some four years before his supposed conversation with the US President took place.

Mr Biden mistakenly referred to Mr Kohl again when he gave the speech for a second time on the same day.

Recent gaffes raise fears over president’s age

Delivering an almost-identical speech in Las Vegas on Sunday, the US President claimed to have talked to Mr Mitterand about the Jan 6 Riots at the G7 meeting in Cornwall.

Mr Biden apparently told world leaders that “America is back”, prompting “Mitterrand from Germany” to offer his opinion.

“Mitterrand from Germany – I mean, from France – looked at me and said, ‘You know, what... why… how long you back for?” he said, apparently referring to Emmanuel Macron.

Mr Mitterand was elected French president in 1981 and remained in office until 1995, dying a year later.