Father of two Mark Pilgrim was killed on the M4 after being thrown from a moving vehicle and left to die in the road, murder squad detectives said today.

A murder inquiry was launched after a car driver struck a heavy object in the left hand lane of the M4 on Friday night.

The woman driver pulled over to the hard shoulder and when she went to investigate what she had struck was horrified to discover the 48-year-old's body.

Detective Superintendent Chris Ward of Thames Valley Police said they were unsure how Mr Pilgrim, of Tilehurst, Reading, had ended up in a vehicle on the motorway between junction 10 for Winnersh and 8/9 for Maidenhead.

Just hours before his body was discovered he was spotted on bus CCTV in the centre of Reading.

Det. Supt. Ward admitted officers did not even know what vehicle Mr Pilgrim had been thrown from.

A post mortem examination revealed he was alive when he was ejected onto the motorway but by the time he was struck by the car he was unconscious or already dead.

He died as a result of multiple injuries consistent with a fall and being struck by a vehicle.

Det. Supt. Ward said: "The lady connected who hit an obstruction then went to see what the obstruction was and discovered the body.

"She contacted us and is a witness in this investigation."

Mr Pilgrim's family were described as "shocked and very upset".

He added: "They are very keen to find out what happened to him and that is what we are trying to piece together."