An American breast cancer surivor has become the first person to swim the Channel non-stop four times in a row.

Sarah Thomas, 37, was heard saying that she felt 'a little sick' when she walked up the beach in Dover, at the end of the fourth leg of her epic challenge.

Due to strong tides in the Channel, the open water ultra marathon swimmer covered a total 130 miles in 54 hours and 10 minutes, during her two round trips between Dover and Cap Gris-Nez.

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She told the BBC afterwards that the most difficult thing during the crossings was the salt water, which burned her throat. She was also stung in the face by a jellyfish.

Endurance swimmer Lewis Pugh posted his congratulations on Twitter, describing her record as an "extraordinary, brilliant and superhuman" performance. "Just when we think we have reached the limit of human endurance, someone is beating the records."

Four swimmers have previously crossed the Channel three times without stopping.

Before embarking on this sporting adventure, she wrote: "This swim is dedicated to all survivors. It is for those of us who prayed for our lives, who desperately wondered what was going to happen, who fought, in pain and fear, to win."

She completed her treatment for breast cancer last year.