Meteorologists have recorded the hottest day in April since 1949, with temperatures reaching 28.7C (83.7F) in the capital reports Sky News.
The Met Office recorded the highest temperature in Northolt, west London on Thursday afternoon. The heat could increase still after Wednesday’s peak temperature was recorded at around 3pm.
After a reading of 25.7C at Heathrow Airport earlier in the day, forecaster Graham Madge said: “We are not expecting that this is the maximum temperature – it will go higher than that.
“It is already warmer than any April temperature last year.”
Thursday’s temperatures follow a high of 25C (77F) on Wednesday afternoon in Gravesend, Kent, and St James’s Park in London. The UK is currently seeing temperatures hotter than in Athens, Greece, where it is 25C (77F), and in Madrid, Spain, where it is 22.2C (77F).
British temperatures are also higher than the temperatures in Rome, Italy, where it is 25C (77F), and in Rio de Janeiro, Brazil, where it is 26C (79F). The scorching heat is a stark contrast to the average maximum temperature for April, which is a mere 11.4C (52.5F).
The Met Office said warm air off the coast of Portugal had been dragged up towards the UK by an area of low pressure over the Atlantic and high pressure over western Europe.