Lisa* is watching Scissor Sisters at a festival in the Lake District, a can of cider in hand, dancing along to the music on a sunny afternoon.

The 30-year-old has a few days off from her job as a veterinary nurse in Gateshead, where she lives with her fiance. She loves going to festivals, especially as “I love meeting new people,” she says.

She is confident and makes friends at the festival very easily. The reason for that? “I’m on a bit of coke,” she says.

It is a crime largely hidden in plain sight – and one many people would barely consider a crime. However, it could land her a maximum sentence of seven years in prison, though for a first offence it is more likely to be a police caution. But she’s unlikely to be caught, especially at a festival, where over the course of the weekend numerous people admit to the Guardian to taking cocaine – or trying to get hold of it – and are seen openly taking it.

By many estimates, use of the class A drug is soaring.…