BBC looks at the key events in the Potters Bar Rail Crash.
May 10, 2002: Seven people die and 76 people are injured when a passenger train travelling from London to Norfolk derails at Potters Bar railway station in Hertfordshire. An investigation is launched by British Transport Police and HM Rail Inspectorate.
May 14, 2002: Health and Safety Executive release an interim report, saying a fault in a set of points south of the station caused the derailment.
May 20, 2002: Jarvis, the company responsible for maintaining the railway track at Potters Bar, produces photographic evidence that supports its theory that sabotage caused the accident.
July 4, 2002: HSE releases a second report, saying nuts missing from adjustable stretcher bars in the points caused the points to "fail catastrophically".
August 2002: Railtrack offers £12m in compensation to victims of the crash.
May 2003: The first anniversary of the crash is greeted with anger from victims and bereaved families that nobody has taken responsibility. They renew calls for a public inquiry.
May 29, 2003: In its third report HSE says the points were poorly maintained with no guidance or instructions for setting up, inspection or maintenance of them. It also said there was no evidence to suggest the crash was caused by sabotage or vandalism
August 2003: British Transport Police are due to present its findings to the Crown Prosecution Service. The investigation includes information from 5,000 people connected to the accident, including witnesses, victims, workers and managers.