Temperatures have topped 40C in the UK for the first time ever, as the sweltering heat fuelled fires and widespread transport disruption across the nation on Tuesday (19 July).A new record for the hottest day ever seen in the UK, of 40.3C, was provisionally recorded in Coningsby, Lincolnshire, beating the previous record of 38.7C in Cambridge three years ago. Heathrow also recorded a temperature above 40C, while 29 other observation sites also provisionally beat 2019's record. Meanwhile, London Fire Brigade declared a major incident due to widespread fires caused by the heat.