Snow has fallen in the home counties as Britain braces for its coldest night of the year.

Arctic air is continuing to move south across the country, with the temperature forecast to drop as low as -15C on Tuesday evening in the Scottish Glens.

This would surpass the current lowest temperature of -10.4C, recorded at Drumnadrochit, a village near Inverness in the Highlands on January 19. 

Already, parts of Buckinghamshire, Oxfordshire and Suffolk have awoken to snow on Tuesday morning.

The Met Office has issued yellow weather warnings for snow and ice across parts of south-east England, London, south-west England, the Midlands and Wales throughout Wednesday, with the north-east of England, Yorkshire and most of Scotland also covered. 

It means disruption to some roads and railways is likely, along with a risk of falls.

Forecasters are expecting two to six centimetres of snow and 10cm on higher ground across the south of England and the Midlands. 

However, "heavy snow" is then expected to sweep across England and Scotland north of Birmingham on Thursday and Friday, of 20cm on lower ground and 40cm on higher ground, prompting another Met Office yellow warning which says it "has the potential to cause significant disruption".

The Met Office said "there is a slight chance that roads may become blocked by deep snow" and "a small chance that communities could be cut off for several days", with "long delays" in travel and power disruption also possible. 

Dan Suri, the Met Office chief meteorologist, said: "Snow is already falling in parts of the north where some travel disruption likely, as well as a chance of some rural communities being cut off. 

"Snow showers will continue through Tuesday here, and Northern Ireland will also be subject to some snow showers, especially over high ground.

"Ice will provide an additional hazard for many with overnight low temperatures well below 0C for many. Further south wintry hazards will develop with parts of England and Wales affected by icy patches and snow in places tonight and likely further snow in parts of the south early Wednesday."

The UK Health Security Agency has extended its "level three cold weather alert" to cover the whole of England until midnight on Thursday, the second-highest alert it can issue. 

It means there is a 90 per cent chance of severely cold weather, icy conditions or heavy snow, which could increase the health risk to vulnerable patients.

The coldest temperature recorded last March was -9.1C in Aboyne, Aberdeenshire, and the coldest March night ever was in 1958, -22.8C at Logie Coldstone, Aberdeenshire.