LONDON: Environmental campaigners were occupying the roof of Britain's parliament Monday in a bid to urge returning lawmakers to overhaul their climate change policies before the UN's key Copenhagen summit.

Around 30 Greenpeace activists evaded security Sunday and clambered onto the roof of the famous Palace of Westminster incentral London, unfurling several yellow banners reading: "Change the politics, save the climate".

The demonstrators waited through the night for Monday morning, when lawmakers return from their summer break, to urge them to sign up to a 12-point manifesto.

"We've got to raise the temperature of the debate because we are really running out of time," said Greenpeace executive director John Sauven.

"Parliament is opening and there is an election looming so this is a golden opportunity for the political parties to really think about the future."

Speaking from the roof, Greenpeace employee Brikesh Singh, 29, fromBangalore in southern India, said the protesters had energy bars and warm clothing to get them through the night.

"This building is considered as the mother of all parliaments and the UK is one of the leading developed countries," the demonstrator said.

"We want them (lawmakers) to get the message loud and clear that if you want a planet-saving deal in Copenhagen we need to change the climate policy."

The December 7-18 United Nations climate summit in Copenhagen will see nations attempt to hammer out a new global climate treaty to replace the Kyoto Protocol which expires in 2012.

A spokesman for London's Metropolitan Police said: "Approximately thirty protestors remain on the roof of theHouses of Parliament.

"The intention of the police is to bring the protestors down off of the roof safely.

"Officers are talking with a representative of the protestors on the ground. All peaceful."

A spokeswoman from the Department for Energy and Climate Change said activism on the subject was welcome but had to respect the law.

"We have a comprehensive plan to transform our economy and society, by investing in green jobs, cleaning up our energy supplies and making our homes energy efficient," she said.

"This week we host vital talks to accelerate the development of clean coal and to progress the Copenhagen deal. It's our domestic record that has given us the credibility we need to press hard for an ambitious global climate deal."

It is not the first breach of security in recent times at the palace.

In March 2004, Greenpeace demonstrators scaled the landmark clock tower on the first anniversary of the invasion of Iraq.

Two months later, fathers' rights campaigners threw condoms full of purple flour in the lower House of Commons, hitting then-prime minister Tony Blair.

Four months on, five protesters got into the chamber to protest during a hunting ban debate.

And protesters got onto the roof in February 2008 to demonstrate against a planned third runway at London's Heathrow airport.