A Stoke Newington runner hopes to put a smile on the faces of young leukaemia sufferers when he attempts a record-breaking London Marathon – in a Mr Happy costume.

The 26-mile run will be all in a day’s work for Andy Jackson, who is entering the race as part of a staggering 1,000-mile dash down the length of the country for Children with Leukaemia. On Sunday, he hopes to break the Guinness World Record for ‘Fastest Book Character’ – currently just over four hours.

“Mr Happy just seemed to fit,” said the 26-year-old. “We want to put smiles on people’s faces. We thought Mr Bump was tempting fate a bit.”

Andy, of Manor Road, was diagnosed with leukaemia at the age of 18. With treatment he made a full recovery, but tragically lost his mother to bowel cancer just three days after he left hospital.

Now he hopes to raise �250,000 – the cost of the bone marrow transplant that saved his life – by running from John o’ Groat’s to Land’s End.

“When I was diagnosed with leukaemia I was just about to go to university and suddenly I couldn’t,” he said. “Everyone else had organised a uni place or a gap year, so I got a bit bored.

“I had always wanted to run a marathon, and I thought it might be the only chance I would get.”

That marathon – two weeks before his bone marrow transplant – gave him the bug for running. Andy has now completed five marathons as Mr Men characters, raising �40,000.

By the time he reaches London, he will have run nearly 750 miles since leaving John o’ Groat’s at the end of February. He hopes to reach Land’s End at the start of May.

To sponsor Andy, visit http://www.mrhappyrunsbritain.org/.