The fatality, which occurred at the wreck-site 60 miles off the Massachusetts coast in the USA, was reported on Divernet last July.

Slater, 46, a member of the Darkstar technical-diving team, was from Gateshead, Tyne & Wear, and the inquest at Crook Coroner’s Court was reported by the Northern Echo.

The diver had been on a week-long trip with buddy Claire Fitzsimmons, who described him as “very experienced, meticulous and careful”, and said that his diving record included many wrecks considerably deeper than the Andrea Doria.

The dive had taken place on 24 July from the boat Ol’ Salty II out of Montauk, New York.

Fitzsimmons told Assistant Coroner for Co Durham and Darlington Dr John Hamilton that she and Slater had planned a dive of no more than two hours, with 20-30 minutes' bottom time to be spent exploring the stern area of the Italian liner, which sank in 1956. The group had waited until the afternoon for rough sea conditions to improve.

Fitzsimmons described it as “weird” that once on the wreck Slater had not stopped to collect any souvenirs when they passed the swimming-pool. She had heard him shouting, and saw that "a large amount of gas” had built up in his drysuit.

Trying to help him to vent it had proved difficult with the heavy equipment in the dark conditions.

The pair had failed to locate the shotline, according to additional reporting from the BBC, although it later turned out that they had been very close to it.

They were unable to prevent Slater’s ascent as the pressure built up in his suit. With Fitzsimmons' computer warning that they were ascending too rapidly, she had been forced to let him go.

She had not been able to surface until 72 minutes later. "It’s properly heartbreaking,” she said. "I just kept hoping they had got him on the surface.”

Crew from the dive-boat had recovered Slater unconscious from the water and carried out CPR but he was later pronounced dead.

Bubbles found in his bloodstream indicated that his rapid ascent from depth had led to his death.

Dr Hamilton said that no equipment faults had been found, and described Slater's death as a tragic accident.

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