Nathan, of Smithy Carr Lane, Brighouse, had suffered from a muscle-weakening disease since the age of two.

He was to have had the life-saving operation at London's Great Ormond Street Hospital on Thursday.

His dad, Steven, said: "He was so close. The surgery wouldn't have cured him but it would have strengthened his heart. It would have saved him – but he was just a few days short."

Football-mad Nathan, a pupil at Brighouse High School, was diagnosed with Ehlers-Danlos Syndrome 11 years ago.

It meant he had problems with his heart, joints and the connective tissue supporting them. He wore callipers and had been in a wheelchair for the past six months after having a operation on his spine.

But Mr Jones, an electrician, and mum Janet said Nathan never let his illness stop him leading a full life.

Mrs Jones, a kitchen assistant at St Joseph's Primary School, Brighouse, said: "He was such a lovely lad and he got the absolute most out of everything.

"He loved his football and was a big Leeds fan. He loved being at school and he loved his music. He was loved by so many people. He just always had a smile on his face."

She added the youngster had a special buggy so he could caddy for his dad when he played golf. It was one of his favourite pastimes and he was about to do it when he complained of feeling unwell. He died shortly after.

She said: "We'll miss him so much. It's like a dream and I'm going to wake up soon."

The couple and Nathan's older brother Ryan, 16, decided Nathan would be kitted out in a Leeds strip for his funeral tomorrow at Park Wood, Elland. People have been asked to wear football shirts or bright colours.

Mr Jones said: "We've got him some boots. He always wanted a pair but he could never wear them so at least he gets to now."

Brighouse High School is planning a memorial for the teenager who had been achieving good academic scores.

Co-head teacher Liz Cresswell said: "Nathan was unfailingly positive, achieved excellent results and made many friends."