THOUSANDS of people travel on the Northern Line each day, but a group of swimmers have gone one better by swimming the distance of the entire line.

The 'Swim the Northern Line' challenge was organised by the Broomfield Park Swimming Club to raise money for the Alzheimer's Society, with 63 athletes ranging from 8 to 68 taking part.

By measuring the distance between each station and then converting this into swimming laps at the Queen Elizabeth Girls' School pool, competitors swam 70 kms over three weeks to cover the entire Northern Line from High Barnet to Morden and back to Edgware.

Duncan Jackman, events organiser of the Southgate based team said: "Some stations were tougher to swim to than others. Getting to Totteridge from High Barnet was a long haul at 107 lengths but Euston to Kings Cross was a doddle at 27."

Charlie Crowfoot, 14, from Cockfosters won the race to Morden in under 16 hours and 12-year-old Kelly-Sarah Floyd from Barnet was the first to make it back to Edgware in 32 hours.

Kelly-Sarah, who started swimming at six-months-old she she was "ecstatic" by the result, especially as she was battling a cold through part of it.

She said, "It was really overwhelming because there were so many older people swimming. I was really pleased I'd won."

The swim-a-thon was part of the swimming club's annual charity schedule, the theme inspired by the High Barnet tube station, which is situated close to club's training pool at the QE Girls' School.

"It was an excellent way to motivate the swimmers and it allowed for different level swimmers to swim at different paces," said Mr. Jackson.

"The younger ones aimed for Camden while the more adept swam the whole distance."

After completing the event, Northern Line manager Jeff Ellis met the swimmers on Friday at High Barnet station to congratulate their achievement.

He said: "The Northern Line is used by thousands of people daily but I do not think than many can say they have actually swum the distance."

The swim-a-thon has so far raised £1,000 for the Alzheimer's Society.