Environmental activists will try to put the future of coal-fired electricity on trial this week, in a court case that will highlight the growing debate over the UK's energy mix.

Six Greenpeace volunteers were in the dock yesterday accused of causing £30,000 damage to Eon's power station at Kingsnorth in Kent by painting a slogan on a chimney. They were protesting at Eon's plans to build a new coal-fired power station next to the existing plant.