A breast cancer survivor has become the first person to swim the English Channel four times non-stop today.

Sarah Thomas, 37, completed the mammoth 84-mile ordeal in 54 hours and 13 minutes and celebrated with champagne and M&Ms at the finish line in Dover.

Her achievement, described as 'mind blowing' by her support team, comes just one year after the swimmer, of Colorado, US, completed breast cancer treatment after being diagnosed with the disease in late 2017.

Mrs Thomas faced windy and choppy conditions, busy shipping lanes and a pod of jellyfish throughout the swim but reached the finish line at 6.30am.

Speaking on the beach moments later, she revealed she thought about quitting after being sick after the second leg, but her team and husband told her to keep going.

Sarah Thomas, 37, has become the first person to swim across the Channel four times non stop in a 54-hour ordeal

Mrs Thomas, of Colorado, US, said the constant intake of salt water was the hardest part of the swim, and it caused her to lose her voice

Breast cancer survivor Mrs Thomas, pictured right at a previous event and left on the beach at Dover this morning after finishing, said she was thrilled to finish and thanked her supporters

Mrs Thomas revealed she was also losing her voice due to the amount of salt water she had taken in.

She told the BBC: 'I'm really tired and I'm losing my voice from all the salt water. Dealing with the salt water was the hardest thing; it really hurts your throat, your mouth and your tongue.

'My crew was really great about helping me stay strong and I knew what to expect from the current and the weather and the cold so I was very prepared for the amount of time that I was going to be in the water.'

Ms Thomas said she was kept fuelled by electrolyte and caffeine-filled drinks as she navigated past 'a lot of jellyfish' during her swim.

She admitted to feeling 'pretty out of it' and was hoping to 'sleep the rest of the day'.

The swimmer added: 'I feel just mostly stunned right now, I just can't believe that we did it.'

Elaine Howley, a member of Ms Thomas's support team, said the swimmer had returned to her accommodation near Folkestone with her family to sleep and recuperate.

Describing her friend's achievement, she said: 'It's unfathomable, it's super human, it's just extraordinary.

'I'm not sure there are enough superlatives out there to explain what this meant on many different levels.'

The swimmer, pictured in the Channel, crossed 84 miles of water in 54 hours

Ms Howley said she first met Ms Thomas in 2013 after she completed a 50-mile swim.

Preparations for the Channel swim began two years ago but were put at risk due to Ms Thomas's cancer treatment.

'The Everest of swimming': Expert lauds breast cancer survivor's Channel efforts Loretta Cox, a specialist trainer at the Channel Swimming Academy, said an average of 300 people a year attempt the 21-mile challenge, with many taking part in relay teams and needing up to two years to prepare. The 63-year-old, who lives in Cornwall, said that on an average single crossing, a swimmer will make 55,000 strokes over the course of 15 hours. 'It's very unusual for people to do more than two crossings,' she said. 'Two is exceptional, three, it was just about heard of, four is just mind-blowing, simply because you've got to be awake for so many hours. 'Most people would go into delirium, it's really exceptional to put your body through that kind of stress.' Ms Cox, who filmed Ms Thomas's final approach to shore at Dover, added: 'One crossing, it's like doing three marathons back to back if you were running.' A successful English Channel swimmer herself, Ms Cox has achieved the triple crown, which also includes the 20-mile channel between Santa Catalina Island and the Californian mainland in the US and the 28.5-mile circumnavigation of Manhattan Island in New York. She said the English Channel crossing is known as 'the Everest of channel swimming' due its technical difficulty and cold water. Advertisement

Ms Howley said: 'Knowing the year that she's been through, with the cancer, it's really important, it's huge for her.

'But she's also pushed out the boundaries of the sport of marathon swimming.'

She added: 'The world of marathon swimming is super proud of her, we're all just thrilled and pleased that she was able to be successful with us.'

In a video live-streamed on Facebook, a small crowd of people could be seen cheering on the swimmer from Colorado as she made her final arrival to shore at Dover.

Ms Thomas has been swimming open-water events since 2007 when she completed a 10km challenge in Colorado and went on to win several races.

She also swam the Channel before in 2012 and set a distance record in 2016 when she swam 80 miles in 56 hours non-stop across Lake Powell in the US.

The shortest distance across the Channel is 21 miles long but goes across shipping lanes, meaning a swim requires preparation to ensure a person stays safe.

Previously, the record distance across the Channel was three times non-stop, which has been successfully completed by four people.

Loretta Cox, a specialist trainer at the Channel Swimming Academy, said an average of 300 people a year attempt the 21-mile challenge, with many taking part in relay teams and needing up to two years to prepare.

The 63-year-old, who lives in Cornwall, said that on an average single crossing, a swimmer will make 55,000 strokes over the course of 15 hours.

'It's very unusual for people to do more than two crossings,' she said.

'Two is exceptional, three, it was just about heard of, four is just mind-blowing, simply because you've got to be awake for so many hours.

This route tracker shows Ms Thomas halfway through the final leg of her mammoth swim

A support team on a boat kept her going by throwing her water bottles filled with nutritional supplements

'Most people would go into delirium, it's really exceptional to put your body through that kind of stress.'

Ms Cox, who filmed Ms Thomas's final approach to shore at Dover, added: 'One crossing, it's like doing three marathons back to back if you were running.'

Photographer Jon Washer, from Boston, who is producing a documentary on Ms Thomas's challenge, also lauded her achievement.

He said: 'This whole experience has been devastatingly hard, but seeing Sarah finish was one of the most emotionally rewarding moments of my life, and I've only known her for about six months.

'My job was to cover her landings, all four of them, from the shores, so I got more than familiar with the Channel Tunnel the last few days, and that felt impossible.

'But knowing what Sarah was just able to do. It is just mind-blowing.'

The Channel Swimming & Piloting Federation congratulated Ms Thomas on 'completing a 4-way historic crossing of the English Channel', describing her on Twitter as 'an absolute legend'.