That's what matters - the process itself and keeping up some forward momentum

Margaret Beckett

The agreement, designed to cut the emissions of greenhouse gases, has been dealt a series of blows since new US President George W Bush rejected the treaty agreed to by his predecessor, Bill Clinton.

The US now prefers the use of carbon sinks - specially planted forests - to combat emissions rather than straightforward cuts in pollution.

And America has been joined by three other countries - Russia, Canada and Australia - who want to reopen the argument about the use of nuclear power in combating global warming.

Prescott flies in

The UK Deputy Prime Minister John Prescott, who negotiated Britain's side during the original Kyoto talks and saw the treaty as one of his foremost achievements in office, will meet Mrs Beckett in Bonn later on Thursday.

Despite being deprived of his former environment brief at the last government reshuffle, Mr Prescott kept ministerial responsibility for climate change.

Mrs Beckett denied there was any confusion about their roles.

Margaret Beckett: Hoping to move the treaty forward

She said Mr Prescott had acted as Mr Blair's "sherpa" after completing a tour of the far east where he held discussions on the issue.

Mrs Beckett told BBC News: "He is coming in briefly, partly to convey to the rest of us the results of some of the bilateral talks he has been having around the world recently on the prime minister's behalf and partly to feed back into that process by seeing what is happening here.

"His word for it is that he is operating as the prime minister's sherpa.

"He has been having discussions in the far east and elsewhere on the PM's behalf to fit into the Genoa side of what discussions can take place there.

Working together

"Obviously, he and I will be working together to do everything we can to keep up the process. That's what matters - the process itself and keeping up some forward momentum."

The US only has observer status at Bonn.

On whether she believed Mr Bush could be persuaded to change his mind on the issue, Mrs Beckett said: "Certainly everyone hopes that, even though the Americans are here only as observers, they are here without any ill will towards the process and are as keen as everyone else to see us make some progress if we can.

"The Japanese have always been very clear that they support the protocol.

"The issue has always been to what extent the Japanese wanted, as everyone does, to work in a way which can hopefully bring the Americans, if not immediately back into the discussions, certainly to making progress on similar lines."

The discussions will last until 22 June.

'Wish lists'

Later, Mrs Beckett told a news conference in Bonn that some countries had "wish lists" on carbon sinks and although the EU had looked into such issues since the Hague talks broke down, there was not unlimited room for manoeuvre.

"What I think the European Union as a group will be trying to do is to get the balance right between maintaining some momentum, making some progress, but not ending up in a position where we have really not agreed anything that will change the position very much as it presently exists."

She added: "I think the bottom line for us and for the EU is to try to maintain some momentum."