This is the heartwarming moment a seven-year-old boy rang a bell to mark the end of his four-year battle with aggressive cancer.

Dressed in a suit and bright red bow tie, Nathan Mowat proudly rang the end of treatment bell at a special ceremony -- signalling he is cancer free.

Mum Gill, 36, described the moment as one of the biggest days in Nathan's battle with acute lymphoblastic leukaemia -- an aggressive cancer of the white blood cells.

Gill from Gourock, Inverclyde, said: "It was a happy, proud and emotional day for us, and it is a massive relief that his treatment is over."

The schoolboy rang the bell at Glasgow Sick Children's Hospital, last Tuesday (Feb 6) where he was joined by friends and family.

Nathan was only three years old when he was diagnosed.

He was pale and had been suffering high temperatures, nosebleeds and night sweats as well as complaining of pains in his chest, tummy and legs.

He has undergone countless procedures during more than three years of treatment as part of a clinical trial.

His family are supporting the Schiehallion Appeal –- a bid to bring more clinical trials to Scotland for young cancer and blood disorder patients.

The findings of Nathan's trials may be used to save the lives of other sick youngsters in the future.

But mum Gill said Nathan, who has been receiving gruelling treatment every day, still has a long way to go in his recovery.

She said: "While a lot of things will change for us as a family now, some things will still be the same.

"He is still at a higher risk of getting mumps, measles, chickenpox, and any spike in temperature would lead to a trip to the hospital.

"It's going to be about six months before I can just treat a temperature at home with Calpol and cuddles."

Gill, who also has daughter Annabel, five, with husband Paul, 41, said the treatment has been "emotionally draining" for the family.

She said: "This is one of the biggest days in Nathan's journey.

"At one point we didn't even know if he was going to be able to start school.

"We have lost so many children we have met along the way so it's a huge accomplishment and sense of achievement to get to this day.

"I am in awe of Nathan. He has powered through it the whole way, continuing to go to school and play football when he could, and never complained.

"But he has lost so much of his childhood. So I hope now this can be a more positive chapter in our lives, and we can move on from it and not let it define us."

Following Nathan's diagnosis, he had four different blocks of treatment as part of the trial.

He had to endure 10 different cocktails of chemotherapies, six bone marrow aspirates, three surgeries, 12 nasal gastric tubes, and 16 blood and platelet transfusions.

Mum Gill is now putting on a ladies night in Greenock on March 3 to raise money for the Schiehallion Appeal.