SAM Waley-Cohen knows his brother Thomas would have relished his victory in one of Britain’s biggest steeplechases on Saturday.

The amateur jockey’s triumph in the King George VI Chase at Kempton Park saw him beat some of the best in the world.

But just as impressive is his dedication in helping his family raise £2m for Oxford Children’s Hospital in memory of Thomas, who died from cancer in 2004, aged 20.

Sam said the experience of watching Thomas’s 10-year battle with the disease convinced him to live life to the max.

Thomas was diagnosed with the rare bone cancer Ewing’s sarcoma in his left leg at the age of 10.

Doctors at the Nuffield Orthopaedic Centre, in Headington, decided to amputate the leg below the knee, before Thomas underwent chemo-therapy at the John Radcliffe Hospital.

But the cancer returned in 2003, and despite radiotherapy, he died in July 2004.

Sam said: “There has always been a part of my psyche of trying to get the most out of every day. When Thomas died, it reinforced how much you need to live every minute of your life.”

Six years on, Sam Waley-Cohen runs his own dental practice and counts flying helicopters, mountaineering, and parachuting among his hobbies.

The 28-year-old has ridden winners at top racecourses including Aintree, Cheltenham and Kempton.

Since Thomas’s death, Sam, his sister Jessica, brother Marcus and their parents Robert and Felicity, who live at Edge Hill, near Banbury, have raised £2m for the children’s hospital, after initially setting a £1m target.

When it opened in 2007, Tom’s Ward was named in his memory.

Sam said: “Thomas never believed he was going to die until really towards the end, because he was a very positive character. He was always going to get better and keep fighting it.

“After he died, we wanted to harness some of his energy and do something positive in his memory.

“We did not want to take something so tragic and make it more negative, but to take whatever positives were possible.”

Among those he recruited to the cause were his friend Kate Middleton. The future Princess famously arrived at a 2008 roller disco, which raised £50,000, dressed in yellow hotpants and pink leggings.

At Kempton on Saturday, Sam, who was riding his father’s horse Long Run, upset a bid by race favourite Kauto Star to become the first five-time winner of the prestigious event. As always, Thomas’s initials were stitched into his racing saddle.

Sam said: “It was an unbelievable day, and one that will live on a long time.

“We have had some good days in the past, but nothing quite on this level.

He added: “Thomas would have been bouncing around with a big grin on his face.”

“There’s always a sort of element of reflection and sadness at all of these things that he would have loved with us.

“To some extent, you enjoy a moment like that, because you know they would have enjoyed it with you.”