The demonstrators sat down in front of the gates of an M11 roadworks site in Wanstead and refused to move when lorries arrived to make deliveries.

Two demonstrators clambered on to a cement mixer and one man was arrested as police struggled to remove him from the gateway of the fortess-style building site.

Two weeks ago, a protestor was crushed under the wheels of a lorry as he tried to prevent work going ahead at the site.

Traffic quickly built up in both directions as police tried to contain the demonstration but protestors spilled out into busy Cambridge Park Road.

As a succession of trucks tried to enter the building site, the protestors had to be repeatedly dragged away and restrained in order to allow building supplies in.

From the lines of traffic, frustrated drivers shouted abuse and honked their car horns as they waited for the congestion to clear.