The protest led to flight delays and people getting out of cars to walk in to the airport

Heathrow travellers suffered delays of more than two hours after climate change activists blockaded the road tunnel into terminals 1, 2 and 3 today.

The activists from the campaign group Plane Stupid barricaded themselves in a van as they protested that the airport’s expansion would have disastrous climate change consequences.

Plane Stupid performed a similar stunt in July that led to arrests, 22 flight cancellations and delays for thousands of travellers.

Neil Keveren, a builder from the village of Harmondsworth, which would be bulldozed for a third runway, was fined after blocking a tunnel in July.

He said: “No one wants to do this. They feel they have to. People feel they have no choice. After we campaigned for year, David Cameron was elected promising