Warner, 50, an experienced diver and instructor from Sutton Coldfield, had been part of a group diving at Cape Wrath, Sutherland in August 2012. He was moving kitted-up from his seat to enter the water when he fell and sustained what later turned out to be a serious liver injury.

Instructors lifted him and gave him the go-ahead to enter the water, but at 88m he began to feel unwell and tried to return to the surface. He had stopped breathing by the time he was back on the boat, and resuscitation attempts proved unsuccessful.

An inquest at Birmingham Coroner’s Court in 2014 returned a verdict of accidental death caused by drowning, combined with a traumatic liver injury.

In 2016 Warner’s widow Debbie sued Scapa Flow Charters for damages. But the Court of Session, Scotland’s supreme civil court, ruled that her action had come too long after the event to be considered, as reported at the time on Divernet.

Now a further action, this time brought in the name of the Warners’ six-year-old son Vincent, has been ruled by the Court of Session not to be time-barred. Scapa Flow Charters is looking to have this decision over-ruled at the Supreme Court in London on 28 June.

A Marine Accidents Investigation Branch inspector told the 2014 inquest that there was no evidence of a formal risk-assessment having been carried out for a kitted-up diver moving between seat and entry-point.

However, skipper Andrew Cuthbertson stated that he was satisfied with safety measures on the boat, and didn’t feel that anything could have been done differently.

The inspector also stated that Warner's injury was so severe that his condition would have reached emergency level even had he not dived.

Debbie Warner, 47, has told The Scotsman that the years since her husband's death have had a "devastating" impact on her and her family. Her husband had learnt shortly before his death that she was expecting another baby, but she had suffered a miscarriage six weeks after he died.

Lawyers had told her there was a clear case of negligence to answer, she told the paper, but with her action time-barred “the only chance was to go to court on my son’s behalf”.

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