The death of a British man who was electrocuted at a dam in St Lucia while on holiday with his three sons could have been prevented by signs warning the public not to enter, a coroner has concluded.

Martin Ellis, 68, from Dartmouth Park, north London, a businessman and the main carer for his disabled wife, was killed when he touched a pipe on the site of the John Compton Dam on the Caribbean island on 16 August last year.

His teenage sons heard him cry out when he went to urinate behind a hut, the roof of which they were sheltering under during a rain shower, and discovered him face down in the mud.

Wasco (Water and Sewage Company), the state-owned entity that runs the dam, said the site was not open to the general public and Ellis should not have been there. However, at an inquest into Ellis’s death on Thursday, St Pancras coroner’s court heard that the only warning sign had been obscured and workers the family had passed had not tried to prevent them proceeding.

The senior coroner for inner north London, Mary Hassell, said: “There’s absolutely no doubt in my mind that if there had been appropriate signage warning the public not to visit the dam then Martin Ellis and his family would not have visited the dam. Instead there was one sign covered in foliage, there was a knee-high chain and there were construction workers who gave directions.”

The court heard that the day after Ellis’s death, the foliage was cut back to show the sign and a new sign was later installed at the site.

Excerpts were read out from a condemnatory report by an insurance investigator, suggesting that the St Lucian authorities’ handling of the case had been affected by a desire to minimise bad publicity.

Phil Peart noted that Edmund Regis, Wasco’s general manager, had been uncooperative initially.

Peart said the island, which relies on tourism, had already suffered a blow from the death of Hannah Defoe, 20, the cousin of the former England striker Jermain Defoe. She died when she dived into a hotel swimming pool on the island in 2012 and was electrocuted.

Peart said: “It’s not hard to see why the island’s government would not welcome another high profile case where another British national has been electrocuted on the island.”

Hassell said the St Lucian authorities had failed to provide the inquest with the electrician’s investigation into why the pipe was live, so she was unable to make a determination on that matter.

Ellis, managing director of a print services company, was the main carer for his wife Amy Silverston, who has MS, and who was in court along with their eldest son Lucian, 20. In testimony, Lucian Ellis related how he had received shocks himself as he had dragged his father away from the pipe, and said they had assumed the knee-high chain was just to prevent vehicular access.

He also said that when police officers had arrived they had stood around joking, and that despite there being more than 10 of them they had asked him to help move his father’s body, a situation Hassell described as “profoundly disappointing”.

After the inquest, Ellis’s eldest son described his father as “an extraordinary man, filled with love and kindness”. He continued: “Without him an enormous void has been created. An example being my mum, Amy, who is severely disabled and no longer has a carer, a breadwinner or a loving husband.”

Hassell said she would be making a prevention of future deaths report to the St Lucian high commissioner in London.