On a cold morning in November, a group of swimmers in Berkshire took to the water wearing special gloves and costumes.
Pulling tow floats behind them, about a half a dozen braved Bray Lake, near Maidenhead, as part of the Blue Space Project.
It is part of a national study that has recruited 480 adults with experience of mild to moderate depression to see if swimming can lead to a reduction in depression and anxiety.
Participant Dom Neil Dwyer said: “I tried lots of different things, from medication to therapy to diet and I heard about cold water swimming and I was really desperate.
“Since then I have not looked back. I have swum through the winter, in the ice, and it’s been amazing.”