Stay up to date with notifications from The IndependentNotifications can be managed in browser preferences.Jump to contentThank you for registeringPlease refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged inAllNewsSportCultureLifestyleHeavy rain and lightning affected the UK overnight, with multiple thunderstorm warnings remaining active across the country on Friday morning. The Met Office predicts an "exceptional spell of hot and humid weather" to persist in the southeast, potentially breaking the record for the hottest June day once more. Temperatures are forecast to reach 40C in parts of Norfolk this afternoon, which would surpass yesterday's record of 36.7C recorded in Merryfield, Somerset. A rare red warning for extreme heat is in effect until 9pm for London, the South East, and the East of England, with high humidity expected to worsen discomfort and health impacts. The severe weather prompted at least three hospitals, including Queen Alexandra Hospital and University Hospital Southampton, to declare critical incidents, resulting in equipment malfunctions like MRI scanners failing and some operations being cancelled. In fullUK heatwave live: Thunderstorms hit Britain as record for June’s hottest day could be broken againThank you for registeringPlease refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged in