Retail theft in the UK has increased by 20% in the past year, with stores suffering £4.8bn-worth of losses in the year to June, according to the latest Global Theft Barometer.

The report also revealed that UK stores have the second-highest rate of staff shrinkage in Europe and that 36.4% of losses are down to employee theft.

Professor Joshua Banfield of the Centre for Retail Research, who compiled the report, said that thieves were hitting convenience stores because they were seen as easier targets for shoplifting.

"There has been a shift away from the multiple stores to smaller convenience stores when it comes to shrinkage," said Banfield. "This is largely because those who commit the thefts recognise that smaller shops are more vulnerable as the multiples step up their security measures."

Banfield advised retailers to report all theft to the police. "They will find it very hard to cut down on shrinkage unless they keep reporting it to the police," he said. "Those responsible will carry on doing it until they realise that they're not going to get away with it."

Spar Tates loss prevention manager Mark Stevenson said there was usually an increase in shrinkage during a recession and warned retailers to keep a close eye on both staff and customers.

"When times are tough, people are more likely to steal from stores, so it's very important that retailers pay close attention to what's going on. If they remain vigilant then it won't affect them as much," he said.