The cause of an aircraft crash near Oxford which killed one of the world's richest men remains a mystery.

An official report says there is "no definite conclusion" as to why the Socata TBM 700 aircraft went into a roll and crashed on its approach to Kidlington airport in December 2003.

French billionaire Paul Louis Halley, 69, died along with his wife, Annik Jacqueline, 63, and Belgian pilot, Hans Brams, 46, when the aircraft struck the ground near the A44 west of the airport.

Mr Halley co-founded the retailer Promodes which merged with French supermarket giant, Carrefour in 1999.

The Halleys had flown from Brussels and the pilot had been cleared to land.

The Air Accident Investigation Branch report said the pilot could have been distracted, become incapacitated, or decided at the last minute not to land but to go around again.