Researchers have found that lager sales increase when the price of sugary drinks goes up.

Although unclear why, the researchers from the London School of Hygiene & Tropical Medicine believe increasing soft drinks’ prices alters people’s spending habits across all beverages and that extra taxes on alcohol as well as sugar could be needed.

The researchers also suggest that subsidies on water or fruit could also help tempt people to switch to something healthier.

The levy will add 18p a litre to drinks with more than 5g of sugar per 100ml and 24p to those with more than 8g per 100ml.

Researchers used data on 31,000 households over a year to model what happens to other purchases when the price of sugary drinks rises. Each 1% increase in the price of the highest-sugar drinks led to a 0.7% fall in their sales, researchers report in the Journal of Epidemiology and Community Health. Yet a 0.23% increase in lager sales also followed, they found.

Richard Smith, of the London School of Hygiene & Tropical Medicine, who led the study, said: “Alcohol is quite different from a can of cola but if the price has gone up [and I don’t buy one] it might be that when I get to the alcohol aisle I’ve got a bit more money in my pocket and maybe I’ll treat myself.” He added: “Beer is roughly equivalent in terms of calories per 100ml as a can of cola and wine has twice as much, let alone the other impacts of alcohol.”