Theresa May must convince Donald Trump to abide by the terms set out in the Paris climate change treaty, Ed Miliband has said.
The former Labour leader pressed the issue of climate change ahead of the prime minister's trip the White House on Friday, when she is expected to meet Trump for the first time.
Miliband said she had a "huge responsibility" as one of the first foreign leaders to meet him, to set an appropriate tone and encourage him to uphold the Paris agreement.
He also suggested that the prime minister offer up some British scientists to help convince him that climate change is real.
Answering Miliband during Prime Minister's Questions, May said: "I recognise the role you have played in looking at this issue of climate change and I hope you recognise the commitment that this government has shown to this issue of climate change with the legislation that we have put through and the changes that we have brought about in terms of the energy sector and uses of different forms of energy.
"The Obama administration obviously signed up to the Paris climate change agreement. We have now done that.
"I would hope that all parties would continue to ensure that that climate change agreement is put into practice."
May also told MPs during the session that she is "not afraid to speak frankly" to Donald Trump thanks to the special relationship between Britain and America.