Our skies are busy, with everything from light aircraft to £100m Typhoon fighter jets above our heads. The first of this five-part series looks at what can go wrong up there, and who’s keeping the skies safe.

We meet air traffic controllers, trainee Typhoon pilots and the family whose passion for vintage aircraft has brought them both joy and tragedy.

The most memorable scene today, however, has to be the amazingly skilful, nerve-shredding journey a search-and-rescue helicopter makes through dense fog to find an injured hiker who will die if they don’t pick her up.