A former Holloway School teacher who drowned on holiday in Sierra Leone was swimming in an area “notorious for its undertow”, an inquest heard this week.

Roger Diski died on February 23 after being swept out to sea while swimming with his daughter Rebekah in an area known for its strong currents.

The sustainable tourism consultant, who was 61, had been a history teacher at Holloway School, in Hilldrop Road, Holloway, for 15 years in the 1970s and 1980s.

His wife Judith De Witt, giving evidence at St Pancras Coroner’s Court on Tuesday, said: “They went for a walk before lunch. They swam across an estuary, and then walked and talked about what a beautiful place it was.

“Then they started off back across this estuary to have their lunch.

“She got to the other side and started to walk, but then he shouted and she ran back, and waved and screamed and called for help.

“People ran and a boat started after him but it could not get there in time.

“It was a place notorious for its undertow, but nobody had checked that before they decided to go swimming. In general, the west coast of Africa is a dodgy place to swim, unless you know exactly what you’re doing.”

The inquest also heard that while Mr Diski, of Huddleston Road, Tufnell Park, seemed to be fit and healthy, he had an undetected heart condition that may have contributed to his death. Pathologist Dr Michael Jarmulowicz said he had a “significantly” enlarged heart.

Coroner Dr Andrew Reid, recording a verdict of accidental death, said: “It appears he did have an underlying, unexpected cardiac disease or cardiac enlargement.

“On the balance of probability, the cause of death was drowning, with his underlying cardiac disease probably contributing to him not surviving.”

Mr Diski, a champion of sustainable and ethical tourism, had been on a working holiday in Sierra Leone when he died.

Despite having no travel experience, he and his wife had founded Rainbow Tours in 1997, which ran trips to South Africa and won a string of awards before they sold up in 2007.

He then became a director of the travel firm Bridge & Wickers.