Seeing his father hooked up to monitors and fighting for his life is an image that will stay with James Cripps for life.

The 16-year-old pupil of St Simon Stock School, Maidstone, vividly remembers the fear and shock he experienced.

To James, dad Andy was the perfect father. He was full of energy and always on the go.

Then that began to change.

Mr Cripps, of Lamberhurst Road, Allington, a chief estimator for a building company, started suffering flu-like symptoms.

“He was tired all the time,” said James. “He would normally be playing golf every weekend and doing stuff every evening, but suddenly he couldn’t do anywhere near as much.

“I remember one day he was mowing the lawn, and then just sat down halfway through and fell asleep.”

The dramatic change in Mr Cripps’s health was a worry not just for James, but also for his brothers Simon, 22, and Jonathan, 25, and their mother, Ann.

Then last September, Mr Cripps was diagnosed with acute myeloid leukemia (AML) and immediately admitted into Maidstone Hospital.

James and his brothers believed their father had simply left home that morning to pick up results from the doctors.

But instead he spent the next four months in hospital.

James said: “Getting the news was such a shock. I just remember the total devastation I felt.

“It was so scary seeing him for the first time, laying there completely helpless and hooked up to machines.”

A couple of days later Mr Cripps’s lung collapsed and he was rushed into intensive care, where he stayed for five days.

His condition stabilised and he was able to have chemotherapy to try to control the AML.

By Christmas Mr Cripps was still not home.

James said: “We went up to see him in the morning and that was OK. Then in the afternoon we went to see other family members and that was really hard. Everyone was there apart from dad.”

By March this year, Mr Cripps, 55, had finished his treatment and was in remission.

But doctors have recommended him for a bone marrow transplant to make sure the illness does not return.

Like little Joe Cawse who we featured last week, Mr Cripps is not a match for any of the 12 million people worldwide on a bone marrow donors’ register.

So, just like Joe, his hope lies in more people signing up for the register, either at sessions like the one held on Wednesday or through the Anthony Nolan Trust.

For James, who suffers from Crohn’s Disease, the heartbreak caused by cancer is something he has witnessed on his numerous visits to Great Ormond Street.

But having his own father diagnosed put a completely different spin on the situation.

James said: “I think if it is someone in your own family then the sheer devastation of everything that is happening hits home.

“Dad being ill has meant a massive life-change for all of us. He used to be so active but now he can’t do anything like as much.

“You try to work round it but it is always there, niggling at the back of your mind.

“We just want as many people to sign the register as possible. Then, hopefully, one of them will be a match for my dad.”