Light-fingered Britons are stealing £3.2 billion of goods through self-service tills each year with almost one in four people admitting taking at least one item without paying for it.

Theft from unmanned checkouts has more than doubled over the past four years, according to a study seen by The Times, raising questions about the viability of the devices in some shops.

The loss equates to £5 of goods per Briton a month, the research suggests. Toiletries, fruit and veg and dairy products are the most common items taken and almost half of people who steal from the checkouts claim to do so regularly.

The study suggests, however, that the high theft rate is not entirely because of a collapse in public morals but because