KALAMUNDA trained open water swimmer Ceinwen Roberts has broken the world record for swimming across one of Britain’s most challenging straits by 17 minutes.

The previous female and overall record for the Bristol Channel swim via Porthcawl to Devon according to Guinness World Records was nine hours and 24 minutes.

Ms Roberts reportedly completed her swim from Porthcawl to Devon in nine hours and seven minutes.

She is recognised as the co-founder of the port to pub swim, a sporting event in which swimmers cross the channel from Fremantle to Rottnest Island.

Ms Roberts is also the only woman to cross between Cottesloe Beach and Rottnest Island three times in one day, swimming a combined 59.1km.

She said taking on the swim was diving into the unknown due to the scarcity of information about the route.

“It was all very unknown as there is not much information out there about this swim and the tides are not as predictable over this channel,” she said.

“We requested to swim at night as we needed to get to Dover the next day for our teammate to swim the channel the next day.

“Looking back, I am glad we swam through the night as the water was so brown and murky and tasted disgusting.

“It was flat and calm on the surface, but the tides below were like nothing I have ever experienced.”

Ms Roberts’ mother, Maida Vale Masters Swimming Club president Andrea Williams said her daughter visited the UK this time as the coach of an open water swimming group.

“They set off at 10pm from a village in Wales to (Devon) on the coast of England,” she said.

“The Bristol Channel is one of the channels with one of highest tide ranges, six to 13m, and the same thing happens in the English Channel.”

Mrs Williams said they’d been training in Lake Leschenaultia in preparation, which is usual for English Channel swimmers since it was so cold and so dark.

“Maida Vale Masters run an open water swim at Lake Leschenaultia every year,” she said.

“As a young girl, (Ceinwen) was allowed to swim in that and that’s when she realised, when she was 12,  she was an open water swimmer instead of a pool swimmer.”

Ms Roberts said her support crew watched and cheered relentlessly through the night and kept a close eye on the swimmers.

“We had to stick within a body length apart from each other,” she said.

“It wasn’t until the morning when we had a few kilometres to go and were swimming on the spot for a while when the crew said we could just go for it to try and beat the record.

“Sprinting as hard as I could for an hour and going seemingly nowhere was exhausting.

“The cliffs where we finished were the highest in England so it was a spectacular scene.”