Former prime minister David Cameron reportedly turned down an offer from Boris Johnson to head up the UN Climate Change Conference known as COP26.
The current PM asked his predecessor to be the president but was rejected, the Daily Telegraph reports, with the Times suggesting that former Tory leader William Hague was also considered.
The disclosure comes after Boris Johnson refused to answer questions about who would take on the job during the event’s launch.
Former clean growth minister Claire O’Neill, who stood down as a Tory MP at the general election, was sacked as president of the talks by the PM’s special adviser, Dominic Cummings.
The government said the post would be a ministerial role in future.
The UN climate talks, to be held in Glasgow in November, are the most important since the Paris Agreement to curb global warming was secured in 2015.
Countries are expected to deliver more ambitious domestic plans for cutting greenhouse gases by 2030, as current proposals are not enough to prevent dangerous temperature rises.
Pressure is also on countries to set out long-term plans for cutting emissions, with the science now clear that the world must reduce greenhouse gases to zero in a matter of decades to avoid the worst impacts of climate change.
The run-up to the talks will require a major diplomatic effort from the UK to secure ambitious climate action from countries – at a time when Britain is also negotiating trade agreements with the EU and other nations.
Asked about the role, Cameron said: “It was an honour to be asked to do that job and I’m very grateful to have been asked.
“But I think it’s best in these situations if you have a government minister doing the job; you then have one line of command rather than, perhaps, two people doing the same thing.”
Speaking to the BBC, he said there are “a lot of things I have already agreed to do this year, not least the work I do for Alzheimer’s Research UK, so I thought it was important that I carried on with that work”.
“But I wish the government well, I wish this climate change conference well, because it’s absolutely vital.
“I’m sure that there will be a government minister, or someone, who will be able to do the job and do it very well. The government has my backing as they go forward.”
Asked about his relationship with Johnson, Cameron declined to answer.