Women-only swimming sessions could hold the key to improving numbers, according to an initiative by leisure centre operator Serco.

The number of women taking part in sessions at the operator’s facilities has more than tripled over the past two years, following the introduction of women-only classes to deliver a more comfortable experience.

Serco introduced the classes at 20 of its leisure centres across England in support of the This Girl Can Swim campaign, part of the nationwide This Girl Can campaign led by Sport England aimed at encouraging women and girls to be more active and participate in sport.

The number of female swimmers fell by more than half a million between 2005-6 and 2015-6 according to Sport England’s Active People survey – over twice the fall seen among men.

However, since Serco introduced women-only classes in January 2016, the number of women taking part has grown from approximately 150 a week to nearly 500.

It reported that 25 per cent of swimmers who have joined the classes have never swum at the centres before and 54 per cent have not swum in the past six months.

“We know fears over body image or swimming ability can be major barriers stopping some women from taking up swimming, so we wanted to do everything we can to create an environment where women can feel comfortable,” said Kate McKnight, head of aquatics at Serco Leisure.

“Some of the changes are very small but they’ve had a really big impact. For example, many women have told us that the poolside robe and towel hooks have made a huge difference, as they used to dread the walk to the pool from the changing rooms.

“The feedback has been fantastic and we’re really pleased more women are taking up swimming as a result.”

Other changes included offering free flip-flops for women who do not want to walk barefoot, employing female poolside assistants to help nervous swimmers relax, and giving tips on exercise and technique.