Davina, who had admitted she was terrified about the prospect of the one-mile swim, managed to conquer her fears and complete the stretch. But she had to cling on to a support kayak as she was taken over to the dock, and was unable to stand once she reached solid land.
The mum-of-three was then carried from the water’s edge to a nearby hotel by a member of the crew – and pictures later posted on the Sports Relief Twitter page showed her wrapped up in blankets as the medical team attempted to raise her core body temperature.
Sports Relief bosses confirmed that she was "undergoing a medical assessment after suffering suspected signs of hypothermia."
Davina, 46, is attempting to travel 500 miles under her own steam, as she heads from Edinburgh to London by running, swimming and cycling for Sports Relief. She has been struggling against severe weather since beginning the seven-day journey on Saturday.
Despite the setback, brave Davina is determined to carry on.
Taking to Twitter to reassure her fans after the swim, she wrote, "I'm ok. That was hairy. Thank you for all your support. I'm about to get on a bike. @sportrelief thank you again." She is due to compete a 14-hour, 130-mile cycle to Keswick.
So far in the BT Sport Relief Challenge: Davina – Beyond Breaking Point, the presenter has pedalled through temperatures of just 3C, plus a further chill from 40mph winds.
Professor Greg Whyte, the trainer for the Sport Relief challenges, said, "These are the worst weather conditions we've seen on any challenge – it's the worst weather ever."