TWO men who died on a boat on the River Ouse in 2019 had been to a pre Christmas party with former colleagues before their deaths, an investigation found.

Ronald Vincent Holmes, 60, and Stephen Jewitt, 63, died from carbon monoxide poisoning after the gas leaked from an on board heater. Their deaths prompted a safety alert urging people to fit carbon monoxide detectors on their boats, a report by the Marine Accident Investigation Branch said.

The report says Mr Holmes, the owner of the boat Diversion, boarded it with two friends at York Marina at about midday on December 3 2019.

They made the four mile trip to York and during the journey the owner switched on the boat's diesel-fuelled cabin heater because it was a cold day.

The group moored near Museum Gardens at about 2pm and spent the afternoon socialising with former colleagues in city centre pubs. One of the two friends had to return home early, so left at about 7.30pm to catch the train.

Mr Holmes and Mr Jewitt had a meal with the group and then returned to Diversion at about 10pm and prepared to go to bed.

The report says the families of the two men became concerned when they had not heard from them the next day and called police.

A police officer went to the boat but found that no one appeared to be on board and was instructed to continue their patrol. The families contacted police again and another officer went on board at about 8pm and found the bodies of the two men. It says "it was apparent that they had prepared themselves to go to bed".

The accident report says: "Diversion’s owner, Ronnie Holmes, was 60 years old and had worked as a power station engineer for over 30 years.

"He retired in 2015 and spent his time carrying out home improvements, fixing motorcycles and boating. Before retirement he had enjoyed scuba diving with friends.

"Stephen Jewitt had retired around the same time as Ronnie, was 63-years-old and had worked as an engineer at the power station, where he met and became friends with Ronnie. Stephen also owned a boat which he had used for diving trips with Ronnie."

It says Diversion was built by Mr Holmes, adding: "The owner had started the construction of Diversion in 1990 and built it over a period of 11 years on land behind his home.

"The boat was launched at York Marina in 2001, where it was based for the next 19 years. The owner used Diversion predominantly on the River Ouse, and frequently entertained family and friends on board."

The annual Marine Accident Investigation Branch highlighted the tragedy in its annual report, emphasising the importance of installing carbon monoxide detectors on boats.

It said the boat did not have a carbon monoxide detector on board. The Marine Accident Investigation Branch issued a Safety Bulletin following the accident.

The branch published its annual report into marine safety last week.

Captain Andrew Moll, chief inspector of marine accidents, said: “The accidents involving leisure and recreational craft that the branch is investigating are quite varied, but two themes are worth mentioning.

"As the tragic accident onboard the motor cruiser Diversion demonstrated, lives are still being lost due to carbon monoxide poisoning.

"There can be many sources of carbon monoxide on a cruising vessel, including the main engines, generators, heaters and cooking appliances. Owners of craft with enclosed accommodation spaces are strongly advised to fit a carbon monoxide alarm suitable for use in the marine environment, and to test it regularly."