Labour has warned that the BBC must appoint an “impartial” journalist to the role of political editor amid reports that Nick Robinson is to step down after 10 years in the high-profile job.

Mr Robinson, who has led the BBC’s political coverage since the days of Tony Blair, will reportedly become a presenter on the Today programme on Radio 4 this autumn.

The 51-year-old is expected to cover the Budget this week before taking time off over the summer to receive further chemotherapy for lung cancer.

Mr Robinson had already made it clear that he would not be able to go back to work full time until September. The Daily Mail reported that when he returns to the BBC it will be on Today, filling the role left open when Evan Davis moved to Newsnight.

Chris Bryant, the shadow Culture, Media and Sport Secretary, said the BBC must ensure that its next political editor was able to remain impartial, amid calls from some right-wing Conservatives for the broadcaster to be stripped of its state funding, and negotiations over the renewal of its charter.

“Obviously it’s one of the most important jobs in British political life,” he said. “The BBC needs to make sure they are absolutely somebody who can deliver impartiality even when they are being howled at by numbskull Tories.”

Mr Bryant added that he hoped suggestions that David Cameron – who made a possibly joking remark about getting rid of the BBC during the election – wanted to “cut the BBC down to size are just flim-flam”.

“Maybe there are ideological free-market Tories who are determined to slash and burn the BBC. [But] I think they’d find themselves getting a great big raspberry from the British public,” he said.