Brewers have reduced the alcohol content in some of Britain’s most popular beers in advance of the new duty regime – which comes into force on 1 August – which will see drinks taxed based on their strength.

Foster’s, Spitfire, Old Speckled Hen and Spitfire are among those that have had their alcohol content reduced, however they continue to be sold to consumer at the same price, The Times has reported.

The reduction in alcohol content has cut the duty payable by 2p to 3p per bottle or can.

A 440ml can of Foster’s was 4% alcohol and has been reduced to 3.7%, while 500ml of Old Speckled Hen Pale Ale has reduced from 5% to 4.8%, for example.

The University of Sheffield’s alcohol research group has estimated that if every brewery cut alcohol by 0.3 points, they would save a total of £250m on duty payments.

Greene King, which produces Old Speckled Hen, admitted to the newspaper that the lower alcohol content was necessary to fight rising costs.

However, Shepherd Neame, which makes Spitfire and Bishops Finger, said the reason behind the reduction was the fact that consumers were “increasingly choosing drinks with a lower alcohol content as part of a healthy lifestyle”.

Heineken said only: “We keep our portfolio under review.”