Temperatures are set to plunge this week, the Met Office has said, after a balmy Bank Holiday weekend and Friday’s 25C scorcher.

A cold Arctic blast will force wind to switch to a northerly direction on Tuesday and Wednesday, the forecaster said, as the early morning mercury is expected to drop to as cold as -5C in the rural north.

The coldest day of the week will be Wednesday, with temperatures dropping some 5 degrees lower than the average for May.

Tom Morgan, Met Office forecaster, said: “As the isobars space apart, the winds will ease down and that’s a recipe for not only one or two fog patches, but also a much colder night.

“So in the countryside we can see a fairly widespread frost to begin the day on Wednesday.…