When you're growing up, you always think of your dad as being invincible. You never imagine that they'll ever come to any kind of harm or experience a potentially life-threatening illness. These things take you by surprise.
In 2006, that's exactly what happened to my family.
My dad, Anthony, had discovered a lump on his gum while shaving one night.. He gave up smoking immediately - something he'd done all of his adult life - and he asked my sister, who was a junior doctor, what to do.
My sister recommended he have a biopsy and some further tests, just to be on the safe side. He thought it'd be fine. We all did. But when the test results came back they confirmed cancerous tumours had been found in his mouth and lymph nodes.
After that, everything happened so quickly. The doctors had to act fast. The cancer was aggressive and it had already spread.
An invasive operation followed, and then there was the radiotherapy. We all tried our best to support him but in reality, we just felt completely helpless. When someone so close to you is on the brink of losing their life, all you want to do is help them in any way you can.
Thankfully, the treatment was a success, and with each day that passed my dad grew stronger. In the years that followed he even ran a 10km race to raise money for Cancer Research UK, as a way of thanking them for their research that helped ensure his survival.
Five years after his treatment ended, we received the happy 'all clear' that his cancer had not returned. Finally, we all breathed a sigh of relief.
Things quickly returned to normal and in June 2011, I took the family out for dinner to celebrate my mum's birthday at a local steakhouse.
We were having a great time, when halfway through the main course I suddenly noticed that my dad was having difficulty swallowing a piece of steak. He couldn't breathe and it dawned on me that he was choking.
While I took in the confusion and panic in the room, my instincts kicked in. I'd never had any first aid training, but I'd seen the basic techniques carried out on TV and realised I had to act quickly. We'd come so close to losing him once before, and now it was happening all over again.
I tried performing back slaps, but they didn't work. I knew I had to persevere and began giving abdominal thrusts. As he slumped over, I was able to push up and in, and the steak was finally dislodged. Dad could breathe again.
The restaurant was completely disrupted. People were stunned, some were crying and other had been calling for help, but nobody had actually known what to do.
If I hadn't been able to perform basic first aid on that day, my dad may not have been alive now, despite his strength in surviving cancer.
Four times as many people of us think more people die from cancer than a lack of first aid, but that's just not true. Up to 140,000 people die each year in situations where first aid could have helped save their lives. This is as many as die from cancer.
That's why I'm backing St John Ambulance's new campaign to raise awareness of the importance of these life saving skills..
Treating cancer directly is above most people's level of understanding - we aren't all doctors and nurses. If my Dad had died from cancer, I wouldn't feel I could have helped any more. I gave my support and did everything I could to be there for him.
But if he'd have died choking at that table, I would have lived on knowing that I could have done something; that saving his life was within my control, and I just didn't know to use those simple steps - it would have torn me apart.
Yes, go on a first aid course but if you don't have time there are other ways to lear; there are smartphone apps, online videos and wallet sized guides, all of which can give you the skills you need to save a life. If you want a free guide then text HELP to 80039 and learn five basic techniques, like choking, that could help you save a stranger, a friend or a loved one.