Faced with what he describes as a "relentless" onslaught of shoplifting incidents, shopkeeper Martin Gaunt says he has carried out more than 50 citizen's arrests in the last two years.
"These people will threaten you, they will raise their fists... There comes a point where you do need to think about your own safety," he says.
Anyone can arrest a person if they have reasonable grounds for suspecting a serious offence is being committed, and waiting for the police would be impractical - but the National Police Chiefs Council says people should call 999 if a crime is taking place.
With shoplifting at a record high in England according to the Home Office, some retailers say they have no choice but to tackle thieves themselves.