The BBC has acknowledged that climate science denier Nigel Lawson “should have been challenged” over incorrect scientific statements made on its flagship news and current affairs programme earlier this year.

Lawson appeared on the Today programme in August and incorrectly claimed that Intergovernmental Panel on Climate Change “has confirmed that there has been no increase in extreme weather events” and “according to the official figures, during this past 10 years, if anything, mean global temperature, average world temperature, has slightly declined”.

The BBC‘s complaints unit today said the interview breached editorial guidelines, and that the organisation accepts that the statements “were, at the least, contestable and should have been challenged”, the Guardian reports.

Bob Ward, policy director of the Grantham Institute at the London School of Economics, told the Guardian: “There needs to be a shift in BBC policy so that these news programmes value due accuracy as much as due impartiality.

“As well as taking account of the rights of marginal voices like Lord Lawson to be heard, the BBC should also take account of the harm that its audiences can experience from the broadcast of inaccurate information.”

The climate science denial campaign group, the Global Warming Policy Forum (GWPF), of which Lawson is founder and chairman, apologised for the errors on twitter three days after the interview after scientists pointed out the mistakes.

The GWPF has a long history of campaigning against climate change policy in the UK and at the international level. It supported President Trump’s promised withdrawal from the Paris Agreement, saying the deal was “pushed through against the declared will of America’s elected representatives”.

It most recently courted controversy by inviting former Australian prime minister Tony Abbott to deliver the group’s annual lecture. In the speech, Abbott repeated a number of familiar climate science denial tropes, including that global warming was “probably doing good” for the planet.

Climate scientists criticised the speech for being “full of falsehoods, miscomprehension, and basic untruths.”