Brothers determined to give their cousin's poorly children a luxury holiday raised almost £3,000 after visiting all 270 London Underground stations in one day.
Richard and Michael Brownnutt, who grew up in Wimbledon, completed the challenge in under 20 hours on Thursday to raise money for their cousin's children who both have Late Infantile Batten Disease.
Ellie Mae, five and Caleb, three, will soon be treated to an all-expenses paid trip to see the sights in London, after their ambitious relatives made it back to Morden just in time in the early hours of Friday morning.
Brothers attempt to visit all 270 tube stations to fund holiday for children with Late Infantile Batten Disease.
Richard Brownnutt, a project manager who lives in Sutton, said: "I'm elated, really, because so much planning went into it - five evenings and one whole day.
"It was touch and go for the last two or three hours whether we'd make it or not but we got into Morden with 20 minutes to spare."
Caleb, three and Ellie Mae, five
He said there wasn't a moment of boredom as they were constantly recording and tracking times according to Guinness World Record guidelines and updating friends on social media.
The brothers set off from Wimbledon Station at 4.53am yesterday and returned to Morden at 12.38am today. As well as visiting all stations they ran 12 miles over the day, to increase speed.
They ran between some stations, such as High Barnet and Cockfosters, because they calculated it would be quicker than travelling all the way back down a line they had already visited.
They did not beat the world record, but they think they may have achieved the record for competitors starting at a south London station.
Recovering from the challenge on Friday afternoon, Mr Brownutt said: "If I don't see a tube for a very long time that would not be a bad thing."
To support their cause, donate via their Justgiving page.