Mr Happy celebrated with four other children’s characters after completing the final leg of his 1,100 mile run from John O’Groats to Land’s End.

Kingston University graduate Andy Jackson, 26, undertook the 10-week challenge to raise funds for Children with Leukaemia, a disease he overcame after being diagnosed aged 18.

His adventures in the 7kg Mr Man costume included being interviewed on the One Show, Grandstand and This Morning, teeing off at Gleneagles, sky diving in Milton Keynes and surfing in Penzance.

He ran the final 10 mile leg from Penzance to Land’s End on Sunday, May 8, with school friends, family members and fellow Children with Leukaemia fund raisers.

He said: “I have thought about this day for a long time. When you are running you build it up in your head, but when you get there it’s relief – I’m happy to have done it.

“I found people in the UK are incredibly kind and generous. It’s often the people who have the least who give the most.”

During the incident packed journey, one support cyclist disappeared with his water supply, prompting him to contact the police to file a missing person report.

A wrong turn in the Scottish highlands added 10 miles to one day’s run, while his father Alan crashed their camper van into a car’s headlights in Pitlochry.

He said his lowest point came during the first three weeks when a knee injury threatened to abort the run.

Mr Jackson left his job as a content manager for website HostelBookers to undertake the challenge, and plans to search for work after a week recuperating in Cuba with his girlfriend.

However, more challenges beckon, including running from Hamburg to Berlin before taking part in that city’s marathon with a German rocket scientist who ran with him during the later stages of his adventure.

Mr Jackson had hoped to raise £250,000, the cost of his own leukaemia treatment, but having generated £40,000 so far he now hopes to achieve £50,000.

See mrhappyrunsbritain.org for details, or donate £3 by texting HAPPY to 70003.