A group of teenagers has visited nearly every London Underground station in one day, raising more than £5,000 for a knife crime prevention charity.

The "Tubeathon" saw 27 groups of young people visiting 271 Tube stations, covering a distance of about 250 miles (402km) across the capital. It is thought to be the first attempt by a group of people to walk the length of the Tube map in a single day.

Organiser Eitan Okrent, 17, said it was important to help other young people. Starting early on Sunday, each team was allocated its Tube stations to visit and a route.

Put together, the 27 routes covered the entire Tube map from Ealing to Epping and from Amersham to Wimbledon. The route did not include Overground and Elizabeth line stations.

The group visited 271 Tube stations, only missing out on Heathrow Airport's terminal two and three stop - because it is not accessible on foot. Eitan, from Barnet, who recruited 120 people for the challenge, said: "Londoners in general know the Tube map, that is their geography of the capital.

"This allows people to see what's above ground what would usually be underground. Some of them have long walks, so they're struggling a bit. But they'll get through it, it's a challenge."

The more than £5,600 raised by the participants will go to Lives Not Knives, a charity that works to prevent youth violence in London by providing mentoring and advice for young people. Speaking about why he chose to fundraise for the charity, the year 13 student said: "We really thought it would be important for young people to go out on a challenge in London to help other young people in the capital, which I think is really special.

"’Lives Not Knives’ do extremely good work helping people get out of school exclusion, mentoring - really helping to stop young people going into knife crime. We know its a big issue in London, so it's a really important issue to solve."

Eitan has previous experience with London Underground challenges, last year missing out on beating the world record for the quickest time to visit every London Underground station. Even so, he managed to complete the challenge in 19 hours and raised £1,400 for a homelessness charity.

"I guess I've always had a weird obsession with the London Underground," he said. "Also, I've always been quite an activist so this kind of challenge appeals to me."