Repeated heatwaves are likely to have cost the UK economy more than £4bn in lost output by the end of July, according to new analysis by the thinktank Verdant, which warns the annual cost could exceed £25bn by 2030. Updating its assessment to include last month’s high temperatures, it now puts the hit to output at £4.4bn. The forecaster has said the UK is on course to record its hottest summer ever, with repeated heatwaves already weighing on trade and output this summer. Almost three-quarters of England has been declared officially in drought after the repeated heatwaves, which have also affected much of Europe. The London mayor, Sadiq Khan, recently pointed to this year’s extreme temperatures as evidence that Labour should stick to its climate targets.