Health visiting is one of those professions that most people think is a bit of a non-job. 'You just sit on sofas and drink tea, don't you? It's not like you're a real nurse, in hospital.'

Well, health visitors are real nurses, with at least three years' training, and they are out there, on their own. No back-up team or support structures to call for help if they're in a dicey situation. No warm lights, tea breaks spent chatting in the canteen, nobody else to ask, 'is this okay, what do you think?'

Over 40 years working in the NHS, Rachael Hearson has been chased down an isolated stairwell by crack-fuelled drug-addicted pimps, threatened by a knife-wielding wife-beater in a hostel, unwittingly visited a brothel.... And that's just the tip of the iceberg.