A Croydon mum has pledged to run 4,530 miles to raise funds for a charity that helped her 12-year-old son in remission from a complex medical condition.

Sarah Milne’s son William was born with intestinal failure and had to spend 80 per cent of the first four years of his life in hospital.

His condition resulted in him receiving a small bowel transplant at Birmingham Children’s Hospital in 2008.

William developed chronic rejection of his bowel in 2014 leading to a second multi-organ transplant in the same year.

He was provided with a new bowel, liver and pancreas.

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Sarah Milne and her son William

Following this transplant William contracted a rare and often fatal complication, graft versus host disease (GvHD).

The condition, which sees the donated organ reject the recipient’s body, left Ms Milne fearing for her son’s future as he became increasingly unwell.

His deteriorating condition prompted Sarah, 46, apply for a place on Caudwell Children’s annual Destination Dreams holiday to Disney World, in Florida.

Caudwell Children is a national charity that provides support to disabled children and their families.

The charity created the holiday opportunity to give 25 children with life threatening illnesses the opportunity to experience a once-in-a-lifetime holiday.

Sarah was delighted when William, an Archbishop Tenison’s High School pupil, was offered a place on the trip in December last year.

Now she says she wants to pay back her debt of gratitude to the charity for the dream holiday.

She said: “It was simply amazing and it’s created so many lasting memories for us.

“William is a huge fan of Star Wars, so to see him training to be a Jedi Knight at Hollywood Studios had me in tears.

“He’s been through so much since he was born but the last two years have been particularly difficult for him.

“I thought I would lose William on a number of occasions.”

Caudwell Children covered the cost of the holiday for Sarah, William, and his 19-year-old sister Hope.

They also provided a team of paediatric doctors and nurses for 24-hour medical care for all the children on the trip.

“It was on the plane back to the UK that I decided that I had to do something to pay back the charity for their generosity,” said Sarah.

“But I was struggling to think what I could do.”

Days after returning from Florida Ms Milne decided she would run the distance between Gatwick and Orlando airports to raise cash for the charity.

Ms Milne first started running 10 years ago when William first became seriously ill.

She said: “I needed to get away from the stress. I found that running gave me a real freedom. When I felt that I couldn’t fight anymore it gave me the ability to run away and take control.”

Unfortunately, Sarah only ran for two years before William’s worsening condition forced her to give up her hobby.

She also caught swine flu four years ago, which damaged her lungs further and left her in intensive care.

She said: “Although I’ve started to run again my condition, and the length of time it’s been since I ran seriously, means that this is going to be an extremely tough challenge.

To clock up the mileage, Ms Milne will compete numerous marathons including the London Maraton and the Kingston Breakfast Run.

A 100-mile run in 24-hours, 10 marathons in 10 days, and running to meetings with friends and family, will also help the mum’s tally.

You can follow Ms Milne’s story on Facebook, or support her via her fundraising page. Those interested in sponsoring her can contact her directly on milnesarah@me.com.

Got a story? Email sean.morrison@london.newsquest.co.uk or call the newsroom on 0208 7226363.