Activist group Plane Stupid has blocked tunnels leading to Heathrow Airport this morning, causing chaos for passengers trying to get to their flights.
The climate change group, who are protesting against proposals to build a third runway at the west London airport, have been blocking the main road entrance since around 7:40am this morning.
They have parked a white van in the middle of the tunnel, draped with a flag reading "No New Runways". The protest is preventing people from getting to Terminals 1, 2 and 3.
— Plane Stupid (@planestupid) November 26, 2015
The protest comes ahead of a debate about airport expansion in parliament today.
It is causing major headaches for drivers, with the M4 stationary southbound and westbound.
Police have been called to scene and have made five arrests already.
Earlier this year the same group caused flight chaos when a dozen activists cut through the wire fence around Heathrow's runway, and lay down on the tarmac covered with blankets.