Drink was a probable factor in the death of a UK pilot who was crushed between his boat and a general cargoship on the River Thames, an accident report has found.

The UK Marine Accident Invesigation Branch (MAIB) said Gordon Coates, 63, a Port of London Authority (PLA) pilot, was attempting to board Misje Rederi's 4,100-dwt Sunmi (built 1993) on 5 October 2016 at Gravesend Reach when the accident occurred.

Coates lifted his right foot onto Sunmi’s deck from his pilot boat Patrol and grasped the deck gate’s uprights with both hands, the report said.

He then appeared to brace himself to step up and across when the pilot launch dropped against Sunmi without warning, causing him to be left hanging by his arms. He was stopped from falling into the water when deckhands grabbed hold of him.

He was then almost sitting on the pilot launch’s deck with his legs between the two vessels in the ‘V’ formed by Patrol’s bow and Sunmi’s side.

As the deckhand and rating struggled to lift the sea pilot on to Sunmi, the angle between the two vessels changed, crushing the sea pilot’s legs between them, the report added.

The difference in freeboard between the two vessels was varying between about 30cm and 130cm.

A pilot ladder had been rigged, but the sea pilot attempted to board by stepping up and through an open gate in the railings onto Sunmi’s main deck which, although adjacent to the ladder, did not form part of the vessel’s designated pilot boarding arrangements, MAIB said.

It added: "The MAIB investigation could not establish whether the fall was a result of the sea pilot’s use of Sunmi’s deck gate, a problem with his knee following recent surgery, loss of co-ordination due to his blood alcohol content being more than double the prescribed limit, or a combination of all three."

But it added: "It is likely that the sea pilot’s consumption of alcohol contributed to his fall."

MAIB also found that low freeboard vessel transfers, though not unusual, had not been assessed by PLA or international pilot authorities, while the deck gate opening was unsuitable to be used as a means of pilot access.

PLA has since revised its drug and alcohol policy, risk assessments covering pilot transfers and fitness assessment procedures.

Sunmi’s manager has been recommended to ensure designated pilot boarding areas are marked and that operations are overseen by a responsible officer.

The postmortem report stated that Coates' death was due to trauma to his left leg.

While both of his legs were crushed in the accident, the popliteal artery in his left leg had been ruptured, leading to massive blood loss.

The toxicology report indicated he had a blood alcohol content of 122mg of alcohol per 100ml of blood.

The pathologist noted: "The alcohol in this man’s blood had been ingested and may have lead to a degree of in-coordination. There were no features...to suggest chronic abuse of alcohol."