Parliament rooftop protesters arrested in London

LONDON (Reuters) - British police arrested 20 environmental protesters who climbed onto the roof of the Houses of Parliament, the latest in a series of security breaches at the London landmark.

The demonstrators from Greenpeace, demanding more government action on climate change, were held on suspicion of trespassing on a protected site after they climbed down, the Metropolitan Police said Monday.

They had used ladders to scale to the roof of the sprawling Parliament complex beside the river Thames and unfurled bright yellow banners saying "Change the politics - Save the climate."

Greenpeace said 55 of its volunteers took part to call for a "new style of politics in Britain" when MPs return from their summer break Monday. About 20 protesters remain on the roof.

In February 2008, protesters opposed to the expansion of Heathrow Airport scaled the roof of parliament and fathers' rights campaigners pelted then-Prime Minister Tony Blair with purple powder inside the House of Commons in 2004.

Greenpeace said the remaining protesters plan to stay until MPs return to work later Monday. They said they told police who they were and what they planned to do before scaling the building.

(Reporting by Peter Griffiths and David Milliken; editing by Michael Roddy)