In India, Ramesh was criticised by the Bharatiya Janata Party for writing a letter to the prime minister suggesting a major shift in India's traditionally hardline position at global climate change talks.

"I can't comment on a letter that I have not seen," US Special Envoy for Climate Change Todd Stern said in London.

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"But I've been very favourably impressed by my interactions with the Environment Minister Jairam Ramesh, and I've had very constructive dealings with Ambassador Shyam Saran.

"I think there's still some way to go, but I think the Indian government is trying to be more constructive. They are trying to see their way through for finding agreeable ways of dealing with core issues like transparency and accountability.

"I do commend them for making, from our point of view, some forward progress," Stern said at the closing press conference.

British Climate Change Minister Ed Miliband also wouldn't comment on the reported letter, but spoke highly of the efforts by Ramesh and Saran to push for a deal with developed countries.

"I think what we see from India is a clear sense that a deal and an agreement on the right terms is in India's interests and that India needs to engage in what Jairam Ramesh calls Per Capita Plus - so it has a per capita approach, but also needs to take domestic action," Miliband said.

"I think that is very welcome and I think India wants to be a deal maker, not a deal breaker. That's my clear sense from both Ambassador Saran and Jairam Ramesh," Miliband added.

The MEF, comprising 16 nations and the 27-state European Union, met in London for informal talks aimed at breaking a long-standing stalemate in global climate change talks.

Talks are deadlocked over US insistence that China, India and other major developing countries undertake binding commitments to slash their greenhouse gas emissions - a product of industrialisation - that cause climate change.

Developing countries argue that climate change has been caused by rich nation-emissions and that the US must first undertake cuts.