He may have weighed little more than a bag of sugar when he was born, but James Cox is throwing all his weight behind a fundraising walk today for Oxford's special care baby unit.

James was born three months early and weighed just 1lb 5oz when he was delivered at the John Radcliffe Hospital in September 2007.

But today he will join his mum Leila, 32, for part of a 24-mile trek across the Ridgeway in Oxfordshire.

Mother and baby are taking part in the MMR Ridgeway Hike, which will raise money for the hospital's special care baby unit, the Oxford Night Shelter and the child grief and bereavement charity SeeSaw.

Mrs Cox, who is a training manager for MMR, a market research company in Wallingford said: "James and I are two of about 24 people from MMR who will take place in the hike.

"The route starts at Sparsholt Firs, near Wantage, and goes through the tip of Berkshire and then back into Oxfordshire near Goring to finish at Carmel College, just South of Wallingford.

"James will be doing about four miles, strapped into a sling on my chest, and then I'll carry on without him for the other 20 miles. We're really looking forward to it and we hope to raise a total of more than £3,000."

The walk will be a remarkable achievement for 10-month-old James, who arrived just 27 weeks and three days in to his mum's pregnancy.

Mrs Cox said: "I had a placental abruption, which means the placenta was coming away and couldn't support James any more. They don't know why this happens."

He was in special care by the time his mum came round from her anaesthetic and her first glimpse of her tiny newborn son was a photograph of him taken by the unit's nurses.

Mrs Cox and her husband Mark, 34, then had to wait three days before they could even hold their son, and then it was only for three minutes.

Mrs Cox said: "During his time in hospital James had two blood transfusions and also developed a gastric bug, which caused his tummy to swell alarmingly. Every day was a rollercoaster.

"There's so much going on - one day your baby can be fine and the next they're poorly. You rely so much on the special care nurses to reassure you. They're so knowledgeable and supportive and that's why we feel so indebted to the unit and want to do all we can to raise money for it.

"James is now almost unrecognisable from the tiny little baby in special care.

"He is 14 pounds seven ounces, loving life and very smiley and I'm sure he's going to enjoy taking part in the hike very much."

Anyone wishing to sponsor James and his mum in the hike should visit www.mycharitypage.com/ MumandJamie A fundraising campaign is under way to raise £4m to refurbish the intensive care nursery at the John Radcliffe Hospital's Special Care Baby Unit. To get involved with fundraising or to find out more call the charity on 01865 221359.