Researchers at British universities found that 17% fewer small packages of sugary confectionery, chocolate and crisps were bought and taken home from supermarkets after they introduced policies to limit unhealthy foods at the tills.

A "dramatic reduction" in the number of purchases of unhealthy food eaten "on the go" was also revealed in the study, funded by the Department of Health and Social Care Policy Research Programme.

Shoppers made 76% fewer purchases of sugary confectionery, chocolate and crisps from supermarkets with the policies, it was observed.

Six of the nine major supermarkets introduced checkout food policies between 2013 and 2017, according to the research, which anonymised the data.

Dr Jean Adams, from the Centre for Diet and Activity Research at the University of Cambridge, who led the study, said: "It may seem obvious that removing unhealthy food options from the checkout would reduce the amount that people buy, but it is evidence such as this that helps build the case for government interventions to improve unhealthy behaviours.

"One such intervention might be to introduce nutritional standards for checkout food as suggested in the Government's recent childhood obesity plan.

"Such a government-led policy might prove attractive to supermarkets as it would provide a level playing field across the sector."

A team of researchers at the Universities of Cambridge, Stirling and Newcastle analysed data from Kantar Worldpanel's Consumer panel for food, beverages and household products.

They looked at the purchases of more than 30,000 UK households during the 12 months before and after the supermarkets introduced checkout food policies.

They also analysed data from 7,500 shoppers who bought "on the go" food from supermarkets with and without the policies between 2016 and 2017.

The researchers were unable to prove definitively that the drop in purchases was due to the policies because the study was not a randomised control trial.

Dr Katrine Ejlerskov, one of the study's authors, said: "Our findings suggest that, by removing sweets and crisps from the checkout, supermarkets can have a positive influence on the types of purchases their shoppers make.

"This would be a relatively simple intervention with the potential to encourage healthier eating.

"Many of these purchases may have been impulse buys, so if the shopper doesn't pick up a chocolate bar at the till, it may be one less chocolate bar that they consume."

Bryony Sinclair, senior policy and public affairs manager at World Cancer Research Fund, said: "We welcome studies such as this, which have been funded by the government, to help understand what policies will encourage people to make healthy choices.

"These evidence-informed policies can then be implemented by governments to create environments that support healthier choices, as eating too much sugar can lead to weight gain, and being overweight or obese increases the risk of 12 different types of cancer.”

PA