Family and friends of a three-year-old boy who was given only weeks to live when he was born will walk from Cambridge to Godmanchester to raise money for hospital units.

For the past two years, more than 40 people have taken part in Sam's Walk, raising £20,000 in the process, a 23-mile trek between Addenbrooke's Hospital, in Cambridge, to The Exhibition pub, in London Road.

On Saturday (September 6), Roy and Kaeron Dodson will be joined for the third walk in honour of their son Sam, who was born 12 weeks early and suffered a bleed on his brain.

Sam, who also has cerebral palsy, was given weeks to live when he was born but in May this year, celebrated his third birthday, mainly due to the special care baby units at Hinchingbrooke Hospital, in Huntingdon, and Addenbrooke's, which benefit from the money raised by the walk.

Mr Dodson, 38, of Bluegate, Godmanchester, said: “Normally we organise the walk for May to mark Sam's birthday, but we have had to postpone it this year. We have got about 40 walkers taking part, but anyone can still take part.

“The atmosphere is generally really good. As the first part getting out of Cambridge can be a bit tricky, I stay behind and make sure everyone is on the right track. When we get to the guided busway it's very easy so I catch up with people and have a chat with them.

“Normally people will find someone at their own pace and have a chat with them throughout.”

Stagecoach is again providing a bus to Cambridge for the walkers while Paul Dyer, landlord of The Exhibition, is putting on food at the end, with donations going to the cause.

Mr Dodson said: “Sam is doing really well at the moment. If you look at him, you'd probably think he's about 18 months to two-years-old but he'll catch up a little. We are waiting for tests to see if he is affected by growth hormones.

“He's not talking and walking yet, but the doctors aren't saying that he shows any signs that he won't, so we're still positive.”

INFORMATION: If you want to sponsor Sam's Walk, visit http://uk.virginmoneygiving.com/team/Samswalk2014.