25 October 2012 Last updated at 14:51 ET

Lancashire M6 metal death crash 'could stay unsolved'

Police say they may never know what led to a piece of metal smashing through a car windscreen and killing a man in a Lancashire motorway crash.

Mark Pearson, 41, of Halifax, West Yorkshire, is thought to have been struck by a rectangular piece of metal 6in (15cm) to 8in (20cm) long.

He was hit on the M6 northbound carriageway near junction 31 at Preston at about 11:00 BST on Wednesday.

A Lancashire Police spokesman said the death was not suspicious.

"We've checked CCTV cameras and there is no suggestion of anybody throwing anything," said the spokesman.

He added: "We may never know why it happened."

The man, driving a Vauxhall Vectra, was taken to hospital by ambulance but died just after arrival.

Sgt Dave Hogarth, from the Road Policing Unit, said: "This appears to be an incredibly tragic incident where in the most unusual of circumstances, a man has sadly lost his life.

"I would appeal to anyone who was on the motorway who witnessed what happened to come forward and contact the police."