Jeremy Corbyn's brother has suggested that the Labour leader could be a climate change sceptic like himself but has refused to speak out because Labour is firmly committed to supporting actions to combat man-made global warming.

Piers Corbyn, who firmly opposes the theory of man-made climate change, said his brother is "very much in favour of debate" on the issue.

The 68-year-old elder brother of the Labour leader is a weather forecaster who bases his predictions on the sun's activity and has ran WeatherAction for 20 years, selling his forecasts mostly to farmers.

He believes climate change is caused by solar activity rather than carbon emissions and has criticised the Government for trying to reduce carbon dioxide emissions.

Asked on This Week why he had yet to convince his brother that humans have no role in climate change, Piers Corbyn said: “I think the situation in the Labour party is that Jeremy has to follow Labour policy and Labour policy includes support for climate change action, within which the climate change idea makes very clear as the science changes then the measures should change, which means now is the time for debate.

"Now, my brother is very much in favour of debate and I totally support his leadership of the party and I look forward to more debate on this issue," he added.

Mr Corbyn has never publicly commented on his brother's theories.

A spokesman for the Labour leader said: "Piers’ comments are a matter for him but Jeremy is going to Paris for the climate change conference this week because he’s committed to the issues that conference is looking to address."

Asked about what his brother's views were on climate change in an interview with The Independent in the summer, Piers said: "When we have these conversations at Christmas, his sons say, 'Dad, why don't you go along with uncle Piers.