The special counsel who called into question Joe Biden’s age and competence in his report on how the US president handled classified documents after his years as vice president is set to be questioned himself on Tuesday.

It comes as House Republicans seek to keep a spotlight on the unflattering assessment of the president.

Robert Hur will appear before the Judiciary Committee to take hours of questions from Republicans and Democrats on his 345-page report, made public last month, in which he concluded that Mr Biden should not face criminal charges for his handling of sensitive government information when he was vice president.

Mr Hur will say in prepared remarks that he was aware of the need to explain why he had decided not to charge the president.

“The need to show my work was especially strong here,” he says in his prepared remarks.

“The Attorney General had appointed me to investigate the actions of the Attorney General’s boss, the sitting President of the United States.

“I knew that for my decision to be credible, I could not simply announce that I recommended no criminal charges and leave it at that. I needed to explain why.”

Mr Hur cautioned that he would not discuss investigative steps or veer from the contents of the report. He said “the evidence and the President himself put his memory squarely at issue”.

Mr Biden told investigators he didn’t remember finding any classified material in his home after his vice presidency or telling his ghostwriter that he found “classified stuff downstairs,” Mr Hur said.

And Mr Biden also didn’t remember how the documents about Afghanistan got into his garage, Mr Hur said.

“My assessment in the report about the relevance of the President’s memory was necessary and accurate and fair.

“Most importantly, what I wrote is what I believe the evidence shows, and what I expect jurors would perceive and believe. I did not sanitise my explanation. Nor did I disparage the President unfairly,” Mr Hur said.

Lawmakers on both sides will try to turn the hearing to their political advantage.

Mr Hur will be the rare witness likely to be vilified all around, by Republicans angry over his decision not to charge the president, and by Democrats for his commentary about Mr Biden.