The British police showed their usual degree of heavy-handiness yesterday, when six people were injured and 14 arrested after clashes between police and climate change protesters near Heathrow airport.

Skirmishes were still continuing last night and protests over the aviation industry’s growing carbon emissions and attempts to expand Heathrow airport are expected to continue until midday today.

Protesters accused the police of using unwarranted force to contain them. “It was an unprovoked, unwarranted attack,” said one spokesman for the camp.

The day of direct action began at noon with a peaceful march to the centre of Harmondsworth, a village which will be affected by the proposed third runway. It was led by people carrying a large sign saying: “We are armed only with peer-reviewed science”.

“We said all along we had no intention of stopping people going on holiday,” said a camp spokeswoman. “We have been peaceful at every point. The police have over-responded at every point and we have been continually smeared as potential terrorists.”