Managers at Didcot power station scaled down production this afternoon following this morning's break-in by 30 Greenpeace protesters.

Fifteen environmental campaigners chained themselves to a conveyor belt carrying coal into Didcot station A, while about 15 others climbed to the top of a 200m-high chimney to paint a slogan, "Blair's Legacy" on the outside.

Shortly after 1pm, managers at the station, run by npower, scaled down coal-powered production to save the remaining coal inside for peak demand at tea-time.

Managers at npower say there is no threat to local electricity supplies at this stage, and have not yet bowed to Greenpeace's demand for them to switch to more-environmentally-friendly gas-powered production at Didcot A.

Protesters are continuing to negotiate with Thames Valley Police officers on site and say they are prepared to stay put for several days.