Working alongside the Community First Responders are the Co-Responders, made up of predominantly RAF and emergency service personnel.

RAF Flight Sgt Stephen Whitlock, 40, has been working as a co-Responder for South Central Ambulance Service (SCAS) for two years. The father-of-two said: “The Royal Air Force has five Co-responding teams, from RAF Brize Norton , RAF Benson and RAF Halton, RAF High Wycombe and Corsham, Wiltshire.

“We are 100-strong and in the past year alone, we have attended 2,037 calls and been stood down on another 1,155. That’s 7,000 man hours, 724 days work and 75,000 miles covered, all for free and on top of our regular jobs. But I don’t think you will find a co-responder who does not love it.”

Sgt Whitlock, who has seen combat in Afghanistan and served as a combat medic in Northern Ireland and Bosnia, said: “The calls come through, the adrenaline rushes in and then you are totally focused on doing what you are trained to do.”

Flt Sgt Whitlock added: “Of course it’s not everyone’s cup of tea. There are shifts when you don’t get a call and others when it is full-on and you find yourself in the back of a car at a road accident doing CPR.

But there is always the feeling that you are making a difference. You often find relatives shaking your hand afterwards, unable to let you go.

“With training, SCAS can turn you from a zero to a hero – and you might just save someone's life.”