The BBC's Tom Heap: The collision happened a few miles short of the terminus

Seven people died when the high-speed express train from Swansea to London crashed into an empty freight train on 19 September 1997.

The crash in west London - just a few miles short of the rail terminus at Paddington - also left 147 people injured.

Along with the corporate manslaughter charge Great Western faces a charge of breaching the Health and Safety at Work Act.

Unlimited fines

The prosecution alleges that Great Western failed to conduct an undertaking to provide transport by rail to members of the public in such a way as to ensure that the public were not exposed to risks to their health and safety.

Both charges carry with them unlimited fines.

Mr Harrison, 52, from Greenford in Middlesex, denied seven charges of manslaughter in January. The judge at the Old Bailey adjourned the case.

The first week in court is expected to be taken up by legal argument before the judge. The prosecution will then open up in about a week.

A public inquiry has been delayed until after the criminal case. It is now expected to begin in September - some two years after the crash.