As the radio crackles to life, there’s a beat of silence then the air ambulance base springs into action. Pilot Graeme Spence makes his way out of the hangar to where his yellow EC135 helicopter waits in the cold sunshine; doctor Jen Hine, 41, and paramedic Dave Griffiths, 37, swing on their fluorescent weatherproof jackets, strap on their helmets with practised movements and grab their heavy bags packed full of pain relief, dressings, syringes and medical instruments, ready to treat a huge