The family of a diver who died in an industrial accident are hoping to trace a man from the region who may have information which could be vital to an 18-month investigation into what happened.

Gary Miller was an experienced, ex-Navy man who was working on an underwater construction project on Canary Wharf in London in November, 2000.

Although he was alone in the water at Blackwall Basin, other divers were on standby, in line with standard procedure.

The emergency services were called immediately they received a signal indicating Mr Miller was in difficulty.

However, after being lifted from the water by the fire service, Mr Miller was pronounced dead at the scene.

The Health and Safety Executive began an investigation into the accident but has not yet reached a conclusion; it is understood anomalies in the evidence have also delayed an inquest.

However, Mr Miller's family are hoping to trace a contractor in his mid-40s who spoke to the diver just before the accident.

Jim Dabbs, who is believed to live in Richmond, North Yorkshire, had cut his finger that morning and was offered a plaster by Mr Miller.

''Mr Dabbs spoke to a local paper after the accident but both the HSE and the police have not been able to track him down,'' said Mr Miller's widow, Marion, of Hornchurch, Essex.

''Not knowing what happened has been torture; it just seems to be dragging on and on,'' she said.

The couple had two sons: eight-year-old Sidney and five-year-old Oliver.

''I keep as much as I can from Oliver but it's difficult with Sidney. I don't know what to say when he asks why no-one knows what happened,'' said Mrs Miller.

Mr Miller's sister, Jacquie (correct) Winch of Upminster, Essex, added: ''The waiting has just been horrendous. It's not about apportioning blame; we are just hoping Mr Dabbs will be able to help the investigation establish what happened.''

Anyone who knows Mr Dabbs or may be able to help the family make contact with him can call (01748) 850407.