On 13 March 1991, a multiple-vehicle collision occurred during foggy conditions on the eastbound carriageway of the M4 motorway near Hungerford, Berkshire, between the Membury service station and junction 14.

Ten people were killed in the pile-up, which involved 51 vehicles, making it one of the deadliest crashes in the history of Britain's motorway network.

A van driver claimed something flew up in front of him, believed to be jackdaws, startling him and causing him to skid into the central reservation, but it was later reported that he fell asleep at the wheel.

Car fuel exploded along with the highly combustible material being carried in one of the vans (possibly deodorant) and the resultant series of explosions closed the carriageway for four days as the charred wrecks were removed and the road surface replaced.

[2] [3] In parliament, MP Michael McNair-Wilson asked why the Thames Valley and Wiltshire police forces had not activated the motorway hazard lights to warn drivers of the patchy fog, but the under-secretary for transport, Christopher Chope, stated that these signs were only used for hazards not readily apparent to drivers and not for adverse weather conditions.