* John Lewis boss says shoplifting an 'epidemic'

* Store theft has dented Primark's profit margin

* Police, courts need to do more - AB Foods CEO

LONDON, Sept 12 (Reuters) - Britain is seeing an "epidemic" of shoplifting, the boss of retailer John Lewis said on Tuesday, as the owner of the Primark fashion chain joined industry calls for the authorities to crack down on the problem, saying its profit margins were suffering.

"It's become an epidemic. Sadly, in the last year we've seen twice as many offences," Sharon White, chair of the John Lewis Partnership that owns department stores and Waitrose supermarkets, told BBC Radio.

On Monday, White called for the UK government to set up a commission to examine the problems faced by town centres, saying they risked becoming "a looting ground for emboldened shoplifters and organised gangs."

On Tuesday, George Weston, the CEO of Primark-owner Associated British Foods, said the fashion chain had stepped up spending on security guards, CCTV and on equipping staff with body cameras to try to combat in-store theft.

"But we need to emphasise, as others have emphasised, the role of the police, the Crown Prosecution Service and magistrates in tackling this problem which is just getting steadily worse," he told Reuters in an interview.

"They are doing more, but it's not enough yet."

Weston said some of the theft was "quite organised" and Primark was also seeing higher levels of anti-social behaviour.

His comments echo those of Tesco CEO Ken Murphy, who earlier this month said Britain's biggest supermarket chain was offering body-cams to staff who need them.

Murphy also called for a change in the law to make abuse and violence towards retail workers a specific offence in Britain.

Store theft is a big problem in the United States too, as a recent surge in inflation has left some consumers struggling to pay their way.

Target, Foot Locker and Dick's Sporting Goods have all warned that profits have been under pressure from loss of inventory due to theft at their stores. (Reporting by James Davey Editing by Mark Potter)