Temperatures have reached 40C for the first time on record in the UK, with 40.2C provisionally recorded at London Heathrow, the Met Office said.

The threshold was hit at 12.50pm as much of the UK sweltered in a heatwave, with parts of England and Wales under a red warning for extreme heat, posing a danger to life, pressure on the NHS and disruption across transport networks.

By 1pm on Tuesday the hottest place in Scotland was Eskdalemuir in Dumfries and Galloway where the temperature was 30.4C, the Met Office said.

On Monday, the mercury rose to 31.3C in Aboyne in Aberdeenshire and Leuchars in Fife.

The extreme heat is fuelled by climate change, which is making every heatwave more intense, frequent and likely, scientists warn.

The new high for daytime temperatures comes after the UK experienced its warmest night on record on Monday, with temperatures remaining in the mid-20s.

The Met Office warned temperatures were still climbing early on Tuesday afternoon.