The father of a young boy from High Wycombe who lost his sight to eye cancer is - for the second time - preparing to run the London Marathon in a bid to help other children and their families who may be facing the same battle.

In a nightmare scenario for any parent, James and Fiona Morley-Smith discovered their son Fintan had a rare form of eye cancer, retinoblastoma, when he was just a five-month-old baby.

Over the following years they watched as Fintan, now seven, endured various arduous treatments, including chemotherapy, radiotherapy, cryotherapy and other pioneering chemo, much of which caused him horrible sickness or pain.

Despite periods when the cancer seemed to be subsiding, Fintan had his right eye removed in 2011 as the tumours inside it were not responding to treatment. His brave battle against the disease continued for another two years, but in 2013 the difficult decision was made to remove Fintan’s remaining eye. He was left blind, but now free of cancer.

But throughout his childhood ordeal and despite the loss of his eyesight, Fintan’s spirit has remained impressively undimmed.

James said: "Fintan coped amazingly throughout his battle with cancer and continues to amaze us in his new life as a visually impaired person. He goes to mainstream school, has learned braille, is learning to play the piano and generally is an outgoing seven year old boy with an unstoppable energy.

"He is still very lively and he’s got a lot of friends and he’s got a buddy dog from Guide Dogs."

Fintan, who has three brothers - Archie, 13, Barnaby, 11 and Oliver, five - is a pupil at the Hamilton Academy, which James described as being, along with Buckinghamshire County Council, "fantastic" in supporting his son.

In 2009, at the height of the then-18-month-old Fintan’s battle with the disease, James first resolved to run the marathon, raising an impressive £8,974 for The Childhood Eye Cancer Trust - CHECT.

During that fundraising quest James cheekily tweeted Stephen Fry on the off-chance of getting some support from the TV star, back when the hugely popular social media site Twitter was relatively young. Sure enough, the QI host himself then tweeted the message on, suggesting people might want to support James - resulting in a massive boost to his sponsorship.

While James, of Coningsby Road, may not have any national treasures of TV backing him this time, it has not damaged his resolve to reach a £4,000 target for CHECT - even though, six years on, he is finding the physical challenge a bit tougher.

He said: "I’m definitely running further than last time in training. We’ve got an additional child and work commitments. It’s definitely tougher and hard - I’d forgotten how much training there was.

"But it’s all about raising awareness of the disease. For every person that donates, every person that reads about it, it's a benefit."

This time, to help spur him on, he has taken on a running partner- Yvette Rogers, a mother of two from High Wycombe whose son used to go to the same school as Fintan.

She added: "I love running - I've done lots of half marathons - and it is really nice to do it (the full marathon) for something so helpful, like this."

To support Team Fintan in their London Marathon quest, go to www.justgiving.com/jamesms/

For more information about CHECT, which supports families and individuals affected by retinoblastoma, go to www.chect.org.uk