Heatwave: Why is the UK so hot at the moment?

The UK is set to see its hottest day on record, with temperatures on Tuesday expected to reach over 40C.

The Met Office has issued a red extreme heat warning covering much of central, northern, and south-east England.

But why has it been so hot recently?

BBC weather presenter Simon King is here to tell us where the hot weather has come from and how long we can expect to see it last for.