How High Street shops are taking on violent shoplifters

Darren has been stabbed during his work as an undercover store detective [Ant Saddington/BBC] Turning up for work each day, Darren fears he could face violence at any given moment.

He has been stabbed with needles and held at gunpoint during an 18-year career on the UK's High Street.

Darren is not a police officer, however, but a store detective - an undercover security guard who poses as a customer to catch thieves in the act.

"You do go home sometimes thinking, 'Why am I in this job?'," he tells the BBC.

"But I see it as if I have to pay for my stuff; everybody has to pay for their stuff."

Shortly before Darren meets the BBC in Northampton, he has foiled a man who swiped chocolate bars from the shelf, pocketed them and walked out.