Sainsbury's bosses have spoken out about a self-checkout 'trick' being used by some customers to get money off their shopping. The supermarket giant has labelled it fraud and has launched a crackdown on the issue.

One trick being used is scanning money-off coupons repeatedly in order to get larger discounts on their shopping. Staff have also been put on alert for anyone presenting "fraudulent" coupons, while Sainsbury's said it had "in-store detectives monitoring for fraudulent attempts".