"Theft is taking someone else's property without their consent – the way that something is stolen does not change that," Mike Schwarz, a partner at Bindmans solicitors, told CNBC.
If caught, offenders could be charged with theft and, depending on the severity of the offence and the number of times they have been caught, could be fined, receive a criminal record or even face jail.
Schwarz added, however, that the research did not come as a surprise.
(Read more: Why your corner store isn't safe from hackers)
"The temptation to steal from a self-service checkout might overwhelm people," he said. "Plus, a lot of people do not have much sympathy with the supermarkets – which seem to be making a lot of money when consumers are struggling."
According to the poll, the most common items to be stolen through self-service checkouts were fruit and vegetables (67 percent), bakery items (41 percent) and confectionery (32 percent).
However Ian Titchener, who publishes Kiosk Europe magazine about the self-service terminal industry, stressed the issue was not with the checkouts themselves.
"The theft is not down to the technology in any way," he said. "It comes down to the customers themselves and the supermarket attendants – who can't be everywhere at once."
Titchener added that the level of theft would most likely be reduced if supermarkets allocated more staff to the self-service checkout area, which were "obviously under-resourced."