Shop owners should greet customers as soon as they enter a store in a bid to deter shoplifters, police have advised.

Lancashire Police said shoplifters can assess how easy it is to steal from a shop by how soon after they enter they are spoken to by a member of staff, in what is known as “the three-to-five second rule”.

“By greeting genuine shoppers, not only does this provide a positive impression of your store, it also deters potential shoplifters,” the force said.

The advice comes as retailers said theft was spiralling out of control with the highest levels across England and Wales since current records began two decades ago.

In July, the Office for National Statistics (ONS) said there were 530,643 reported shoplifting offences in the year to March, which is a 20% increase from the previous year.

British Retailers Association director Tom Ironside said the ONS figures “prove what retailers have long been telling us – that retail theft is spiralling out of control”.

He said such theft triggered violence and abuse towards staff and cost retailers and customers £2.2bn a year.

Lancashire Police issued the advice to retailers in an online guide – Securing your shop from shoplifters – as part of Operation Vulture, which tackles shoplifting.

“If a thief thinks they’ve been spotted they’re more likely to leave,” the guide said.

But it also urged caution as “shoplifters could respond aggressively when challenged”.

It advised staff to keep a safe distance, ask if the person needed help or a basket, and to step away and alert a manager or security if they felt uncomfortable.

The force also warned that thieves targeted stores where there was only one member of staff, “so have a few members of staff and make sure they’re trained in how to spot shoplifters”.

It said Operation Vulture also involved hotspot patrols, increased visibility in targeted areas, and working with retailers to understand retail crime and identify offenders.