Prince: Mr Archer was not looking well. He was breathing short, sharp gasps and was very red.

I couldn’t find a pulse and then the gasps stopped altogether, and he slumped forward. It happened very quickly, like just two to three seconds.

In a moment of crisis, you don’t try to be a hero and just remember what they told you in training and calmly assess the situation and fall back on your training.

I had never done CPR for real – I was just a 21-year-old medical student, used to having seniors around me. Suddenly it felt like it was just me and Mr Archer.

I was full of adrenalin and on my first compression, I heard a pop and knew I had cracked Mr Archer’s ribs. This didn’t deter me as I knew this could happen and it was a sign I was doing it correctly. There is so much tissue and muscle around the heart, CPR needs to be firm.

When I heard Mr Archer was stable enough to be transported to hospital, I was so pleased.

Paul: I was lucky in terms of where and when I had my cardiac arrest but most won’t be. It could be anywhere, anytime. It could be your mum or dad, son or daughter, friends, a neighbour or even your grandchildren.

Don’t wait for a tragedy - simple things done right can make a massive difference.