Fatty foods such as chips and chocolate bars should cost more, say medical researchers.

An increase in taxes on foods high in fat, sugar and salt would cut heart and stroke deaths by 1.7%, according to the study in the Journal of Epidemiology and Community Health.

It is the first time anyone has tried to work out the impact of taxes on a person’s health.

The researchers from the Department for Public Health initially taxed only dairy products which had high levels of saturated fat but found that people merely switched to different unhealthy foods.

However, critics argue that ‘fat taxes’ undermine people’s need to eat healthily.

Director of the Dairy Council, Dr Judith Bryans, said: “It does not take into account the fact that some foods which contain fat, salt and sugar also contain a plethora of beneficial nutrients.

“Increasing the cost of these foods is therefore likely to have a detrimental effect on the overall quality of the diets of those with the lowest incomes.”

Former prime minister Tony Blair dismissed the idea in 2004 when at a Labour Party Convention he said that people didn’t want a “nanny state”.