POPULAR television presenter and university professor Professor Alice Roberts has officially opened some new stone steps down to the River Frome for the Farleigh and District Swimming Club.

Founded in 1933, the Club is believed to be the oldest and only (non-naturist) river swimming club in the country, with around 5,000 members.

Professor Roberts, 49, from Bristol, is a wild swimming enthusiast and presented a one-hour documentary on BBC Four on the past-time in August 2010 inspired by Roger Deakin's book Waterlog.

Quoting from Mr Deakin’s book, Professor Roberts urged club members to support the campaign to make UK rivers safer for public bathing by reducing pollution.

“We desperately need to improve the water quality in our rivers,” she said. “For the ocean to thrive, we must look to the source that feeds it: our rivers.

“Rivers are the arteries of our blue planet but are treated like open sewers. Only 14 per cent meet good ecological status and one in four pose a serious risk to human health.

“Please sign the petition @sascampaigns calling for 200 river bathing waters by 2030.”

Rob Fryer, the Club’s chairman, who lives in Warminster and is a town councillor there, said the opening was “highly successful, and had attracted members from all over the country.

“We had people here from Bristol, Cambridge and Derby,” said Mr Fryer, who has written a book on the club’s history.

The Yorkshire stone steps and a metal handrail have been installed at a cost of £12,000 to make it easier and safer for wild swimmers to get in and out of the river.

The club has also installed a six-metre high flagpole and unfurled a two-yard with the club logo on to advertise its presence.

Mr Fryer’s son Michael, who used to collect the fees from members, also travelled from Aylesbury to blow a fanfare on his bugle.

He was wearing a 12th century bi-cocket hat to symbolise how long people have been swimming in the river.

 Professor Roberts was unable to swim, as she was wearing a protective boot on her left leg.

Born in Westbury on Trym, near Bristol, the 49-year mother of one is a biological anthropologist, biologist, TV presenter and author, as well as being a Vice President of the Humanists UK and its president last year.

Since 2012 she has been Professor of the Public Engagement in Science at the University of Birmingham.