A boat owner from Bourne End who had fallen into the River Thames at least three times due to “alcohol intoxication” was found dead partially submerged in the water by a shocked family, an inquest heard.

Emergency services were deployed to Bourne End Marina just before midnight on April 21 after a mother and son found the body of Andrew Bonner-Walter, 54, “trapped” in some railings on a jetty with his head submerged in the water.

Describing the events of the night in a statement to Buckinghamshire Coroner’s Court on Wednesday, Natalie Milner, who has moored her boat in Bourne End for around five years, said she was at the marina that night with her son and other family members to put supplies on her boat ahead of a trip.

She told how her son, who was walking ahead of her on the jetty, was the first to see Mr Bonner-Walter – a producer who lived in the marina on his boat Tipsy Too - with his leg “twisted” in the railings.

She said: “[My son] was walking ahead of me and he stopped. I assumed he stopped because he was carrying heavy items. When I got to where he was, I saw a plastic carrier bag. Then he said ‘I think someone is in there’.

“At first I saw trainers - then I realised there was a person’s legs in those trainers. The person’s head and part of the chest was in the river.

“It took me a minute or so to process the fact that we had seen a dead body, then I phoned police.”

Thames Valley Police officers raced to the scene, with PC Colin Targett among those who attempted to rescue Mr Bonner-Walter from the river.

He said: “He was hanging by his trapped foot with his head submerged. He was not moving or struggling and he was cold to the touch. We tried to pull the body out of the river but we experienced a lot of difficulties because of the sheer weight of the body.”

After his body was eventually recovered, Mr Bonner-Walter was taken to Wexham Park Hospital, where medical notes revealed he had been treated at the same hospital just days before on April 7 having fallen into the river “while possibly intoxicated”.

He was officially declared dead at 2.17am on April 22. A post-mortem found that Mr Bonner-Walter had ethanol levels of 297mg per 100ml of blood. The legal drink drive limit is 80mg in 100ml of blood.

Dr Peter Johnson, who carried out the post-mortem, said it was “likely alcohol was a factor in his falling into the water and being unable to get himself out again” and found that Mr Bonner-Walter had a history of alcohol addiction.

When police officers searched the area where the incident took place, a carrier bag from the Co Op containing two bottles of white wine were found.

PC Laura Burns told the inquest that CCTV footage showed Mr Bonner-Walter buying the alcohol in the store at 8.50pm that evening, however video footage from the marina itself did not capture the moment he fell into the water because it was too dark.

She also said the marina manager was aware of four incidents where Mr Bonner-Walter had fallen into the river – one through “sailor error” and the other three believed to be alcohol-related.

Senior Coroner for Bucks, Crispin Butler, recorded a conclusion of misadventure, with the medical cause of death being drowning associated with alcohol intoxication.