Breaking news - UK records new high temperature of 40°C for the first time
The temperature has hit 40.2 (104.3F) at Heathrow Airport - a new all-time UK record.
Earlier today, 39.1C (102.3F) was recorded in Charlwood, Surrey - breaking the previous record of 38.7C (101.7F) set in 2019 at Cambridge Botanic Garden.
Temperatures as high as 41C (105.8F) are forecast today, with much of England still under the first ever red weather warning.
The night-time record was broken overnight, as Kenley in Surrey hit 25.8C (78.4F), while Kew Gardens and Heathrow surpassed the previous temperature record by noon on Tuesday, recording temperatures of 38.8C (101.8F).
The sweltering heat has already caused significant travel disruption, with Luton Airport forced to suspend flights on Monday because of a defect in the runway.
On Tuesday, police said a section of a dual carriageway in Cambridgeshire was left looking like a "skatepark" after it warped in the heat.
Rail users have been warned of delays and cancellations as the heat takes its toll on the country's infrastructure.
There will be no Thameslink or Great Northern trains running in any location north of London, from London Blackfriars via St Pancras, or from London King's Cross or London Moorgate.
Merseyrail said the number of trains running and journey times will be "seriously affected" and some routes closed completely.
LNER will run no trains from south of York and south of Leeds to London King's Cross