Shoppers admitted to a variety of techniques to avoid paying for items, such as slipping extra bits of shopping into their bags without scanning them, and selecting cheaper fruit and vegetable items when weighing them.

The figures, revealed in a study of almost 5000 shoppers by money-saving website, also showed a widespread proclivity for selecting ‘small’ when asked for the size of items such as salad boxes.

Half of those who admitted to cheating the system admitted to selecting a cheaper item when putting loose items through.

The evil genius of scamming the self service check-out is that should a customer be caught with an item that has not been scanned, they can claim it was a mistake.

While a third of people do cheat at self service check-outs, half of those who do not steal admitted the reason for staying honest was fear of being caught.

Earlier this year, ‘celebrity’ chef Antony Worrall Thompson was caught shoplifting five times in the space of 16 days in his local Tesco.

He was caught on camera bagging up goods at the self-check-out without paying.