The BBC has apologised to viewers for airing an interview with Lord Lawson in which he was allowed to deny climate change without challenge.

The corporation has now admitted that the interview was a breach of its own editorial guidelines, after the former Government minister claimed that global temperatures have not risen in the past decade.

Lord Lawson made the comments in an interview on BBC Radio 4’s Today programme, prompting a wave of complaints from listeners.

Initially, the programme rejected the complaints on the grounds that Lord Lawson’s views were aligned with those of the “current US administration”.

But a letter seen by the Guardian has now revealed that the BBC has since retracted this position and accepts the interview breached impartiality guidelines.

The controversy was caused in August when Lord Lawson said that a UN body on climate change had “confirmed that there had been no increase in extreme weather events”.

He added that “during this past 10 years, if anything, mean global temperature, average world temperature, has slightly declined.”

However, the BBC complaints unit has now determined that these statements “should have been challenged.”

Writing to one viewer who had made a complaint, Colin Tregear, BBC complaints director, said: “I hope you’ll accept my apologies, on behalf of the BBC, for the breach of editorial standards you identified.”