Swimmers and bathers have been warned again to stay out of a Bradford reservoir which has claimed the lives of three people in 15 years.

The warning comes after the Telegraph & Argus was sent a picture from a concerned passer-by who saw a group of youngsters in a paddling pool floating in the middle of Chellow Dene reservoir.

It is the same location where 22-year-old Aamir Ahmed, of Heaton, drowned just over three years ago.

Philip Balmforth, of Allerton, said: “All were Eastern European and were shouting to each other and a male on the bank in a ‘not understood’ (to me) language.

“The large inflatable paddling pool was being moved by the means of one of the group slipping over the side and using his legs – and we wonder why things happen when someone becomes deceased.

“This is despite all the warning signs erected warning people about green algae.”

Geoff Lomax, Yorkshire Water’s recreation and catchment manager, said the company was not aware the reservoir was a hotspot for illegal swimming.

But he did say hot weather increased the number of people taking a dip in one of its 120 reservoirs across the region.

He said: “Reservoirs might seem like a good place to take a swim to cool down, but they are extremely dangerous due to the chilling temperatures and the strong undercurrents beneath the surface. When fatalities occur, it’s often the temperature of the water which is the most significant factor.

“Reservoirs are deep and the water in them doesn’t flow like in rivers or the sea so the temperature rarely rises much above 12C.

“What began as a day out in the sunshine can turn to tragedy within minutes if you decide to take a dip.

“It really doesn’t matter how well you can swim as it’s the cold which can kill you.”

At an inquest into Mr Ahmed’s death it was heard that he had been at the reservoir with his girlfriend, Gulnaz Akhtar. Close to the bench where they had been sitting was an embankment with a four-foot drop into the water, covered in algae.

Forensic pathologist Alfredo Walker concluded that Mr Ahmed had fallen, hit the back of his head on the concrete embankment and rolled into the water in an intoxicated state.

Miss Akhtar went into the water to try to pull him out, but quickly got into difficulties and was rescued by passers-by who formed a human chain to reach her.

Witnesses who attempted a rescue spoke of deeply-shelving water and very strong currents. Toxicology tests later showed Mr Ahmed had been drinking and that he was more than twice the legal limit for driving.