Snow replaced spring sunshine and warm temperatures in London on Thursday as a cold snap swept across the country.
The sudden drop in temperatures is being caused by Arctic air coming south across the UK behind a cold front which has brought, in some places, snow.
"As it crosses the south of the UK for the start of Thursday, it could bring some slight snow coverings to south-eastern areas," the Met Office said.
The cold weather is expected to last until the weekend when slightly warmer conditions will come in from the west, bringing unsettled conditions.
Until then, temperatures are expected to be half those reached last week, when many areas basked in glorious sunshine and highs of 20C.
Meteorologist Matty Box said that there was currently a "cold air mass" over the UK.
"There is an ice warning out at the moment. If there’s any melt and it refreezes over night then there’s an ice risk," Mr Box said.
"I suspect there will be a similar risk for Thursday night to Friday morning," he explained.