I'm not supposed to run, but after my daughter became seriously ill I ran the London Marathon

My tendonitis didn’t matter anymore – I was going to do it whether my knees liked it or not

"Remembering why you are running gets you through, and the sense of achievement you feel at the end is immense"

I’m not a runner. Because of tendonitis in my knees, I’m supposed to avoid high impact sport, and running can put me in quite a lot of pain. But when my daughter Millie was diagnosed with Neuroblastoma, a rare and aggressive form of cancer that affects mostly children, this didn’t matter anymore. I was going to run whether my knees liked it or not.

Millie was admitted to hospital when she was just seven months old, and has been in out of Great Ormond Street Hospital (GOSH) more or less ever since. She is now five, and doesn’t properly understand it yet. Although clearly she has some idea that something isn’t quite right, from all the hospital visits, surgeries, scans, x-rays, blood tests, and chemotherapy.

Millie has coped with her situation better than we could ever have expected and we are very proud of her. On the second night after her first major surgery, for example, she was in bed giggling so much that the surgeon said they thought she was well enough to go home. She also spent eight hours of her third birthday in hospital having chemotherapy dressed as a witch, casting spells and making everyone laugh.

The Cullips pose for a family photo

While she was going through her treatment I wished I could wave a magic wand a make it all go away, but I couldn’t. However, I soon realised that I could run the London marathon to raise money for the hospital – and not just for Millie, but for every child who finds themselves there.

Running just over 26 miles was painful, but also completely worth it. The support from the crowds and the volunteers from start to finish was amazing. At the beginning I was high-fiving almost everyone offering a hand. I actually started cramping from around half way but still managed to get round in 4h 05mins, with a huge debt to the St John’s Ambulance team and the encouragement of the hundreds and thousands of people that lined the streets that day.

Remembering why you are running gets you through, and the sense of achievement you feel at the end is immense. Immediately after finishing I made my way to join Millie on the Mall to watch my wife, who also ran. You can see the pride and excitement on Millie’s face as she recognised her mummy coming into view. Together we helped to raise over £22,000 for GOSH.

Millie cheers on her mother while she finishes the 2015 London Marathon

I am thrilled to report that Millie is now in remission. We attend GOSH every three months for scans and check-ups. Millie started school this September and looks forward to it every day.

If you’re thinking about running a marathon to raise money for a worthwhile cause, I cannot recommend it enough. If you’re unsure, I hope my story helps demonstrate that it can be done. Because as I asked myself at the time – in the grand scheme of things, who cares if my knees hurt?

Win a place in the 2016 London Marathon

You can take on the world's most iconic marathon by bidding on the marathon lot on the Give to GOSH auction. This prize will secure you a spot on the starting line for one of the UK’s most famous and incredible sporting events.

To bid in our online auction in aid of Great Ormond Street Hospital please visit www.givergy.com/charity/gosh

For donations to our Give to GOSH appeal please go to www.gosh.org/givetogosh