Arrests have been made as protestors against Heathrow’s third runway chained themselves to a car.

Motorists were warned of possible delays as activists blocked a road and tunnel leading to Terminals 2 and 3 at the UK’s busiest airport.

Police arrested two demonstrators for obstructing a highway, using two cars to block the tunnel, and said they are working with staff at the airport to remove those locked to a third vehicle.

The protest group, Rising Up! said it was acting to oppose expansion of the west London hub.

A plan to build a third runway at Heathrow was chosen in October as the government’s preferred option for increasing airport capacity in south-east England.

A Heathrow spokesman said: “Protest activity is currently taking place in the in-bound tunnel to Terminals 2 and 3.

“Contraflow traffic procedures are now in place, however, traffic is heavier than usual in the area.

“We are working with the authorities to resolve the issue but advise passengers using Terminal 2 and 3 today to allow extra time for their journeys to the airport.

“Heathrow supports the right to peaceful protest within the law, but the safety and security of our passengers, aircraft and colleagues together with the smooth running of the operation is paramount.”

He advised passengers to allow more time to drive into the central area of the airport.