New Met Office climate map exhibits hazard areas affected by -20C huge chill tonight as Trafalgar Square fountains freeze

Britain has been gripped by an arctic chill as temperatures are set to plummet as low as -20C in some parts of the UK tonight. 

People are waking up to a frosty morning after sub-zero temperatures iced parts of the country, including London where even the fountain in Trafalgar Square has been frozen solid. 

The mercury will continue to fall in the coming days, potentially reaching -20C in northern parts of the UK on Friday night, the Met Office has forecast.

Yellow weather warnings for ice are in place across the majority of Wales and Northern Ireland, as well as large parts east of England until 10am on Friday. A warning for ice is in place in 

There is also a yellow warning for ice and snow in northern Scotland, where up to 10cm (4in) of snow is expected to fall. 

Heavy snow in North Yorkshire also saw 23 visitors and six staff trapped inside the Tan Hill Inn in Richmond, which claims to be Britain’s highest public house at 1,732 feet (528m) above sea level. 

Customers had trekked to the world famous boozer on Saturday night and later became ‘snowed in’ following the heavy snowfall. 

While a number of guests had been able to leave on Tuesday, it was not until Thursday that the staff were able to make their own exit. 

Staff were finally relieved of their duties after Elle Applegarth, 25, from Washington, Sunderland, arrived to clock in yesterday.

Ms Applegarth, who works at the pub as a member of the bar staff, had managed to avoid the lock in narrowly.

‘I think a lot of them had cabin fever. It’s all fun at first but then the reality kicks in, you have to keep on going.

‘The thing is, the staff have to keep working once they’re here.

‘I got here about 12.30pm (on Thursday) – everyone was just ready to leave. 

‘(Someone) started crying, and I was like ‘has it been that bad?’ and she went ‘no, I’m just tired now!”

She added: ‘I had to leave early so I managed to miss getting locked in.

‘The roads have been so bad. There are places where you can see it’s near enough four foot. The snow is just so high.’

Met Office meteorologist Liam Eslick said: ‘It’s going to be another cold couple of days, and recovering into the early part of next week.

‘Anywhere across the UK is likely to see those temperatures dipping below freezing and likely to see quite severe frost and ice to form overnight tonight.’

Freezing fog is also forecast overnight across central and south-east England, and parts of Wales.

It ‘could be quite stubborn to clear’ on Friday morning and may cling on in some areas throughout the day, Mr Eslick said, adding that parts where it lifts will be bright and sunny.

Devon and Cornwall could turn cloudy with some outbreaks of rain as a front moves towards the south-west, and Dartmoor and Exmoor are likely to see snow.

There is a chance of snow across northern Scotland and possibly the very north-east of England on Friday too.

Mr Eslick said: ‘Because that rain is falling on some pretty cold ground, it is likely to turn to icy conditions as well.

‘So, we are telling people to take care if you are travelling around with these cold temperatures for tomorrow, but at least it’s quite settled and away from that freezing fog it will be nice, bright and sunny’.

Friday night is predicted to bring the lowest temperatures of the cold snap in parts of Scotland and northern England, with temperatures between -15C and -20C possible.

Mr Eslick said: ‘That’s probably the lowest limits that we’re … expecting, we probably don’t really expect many places to get close to minus 20C, but we could see one or two places that could just touch that mark overnight Friday into Saturday.

‘Just because it’s, again, still conditions, it’s high pressure, not a lot of wind and under clear skies as well.

‘Especially where there’s still snow on the ground across Scotland and northern England, that’s sort of a perfect scenario to see those temperatures just plummet from Friday night into Saturday morning as well.’

Mr Eslick said: ‘Saturday is still going to be another cold one, unfortunately.’

However, clouds will come in from the west which should prevent temperatures dropping as quickly, he said.

The meteorologist added: ‘Sunday will still be a chilly one, but not as cold as what we’ve seen for today and for tomorrow.

‘By Monday, we are expecting the temperatures to come back up to what we would expect for this time of year, which is around sort of 7C (or) 8C’.

Manchester Airport closed both its runways on Thursday morning ‘due to significant levels of snow’ but they were later reopened.

The airport warned that some flights may be delayed, and advised passengers to check with their airline for the latest information.

Transport for Wales closed some rail lines in the country due to track damage following a period of ‘heavy wind, rain and snow’.

Buses are also replacing trains between Llandudno Junction and Blaenau Ffestiniog until at least Monday.

Meanwhile, hundreds of schools in Scotland and around 90 in Wales were shut today due to the wintery weather. 

Significant travel disruption was also caused by the snow in Devon and Cornwall yesterday, with some roads closed and motorists stationary for ‘long periods of time’, a joint statement from Devon and Cornwall Police and Devon County Council Highways said.

Snow ploughs became stuck in queues of traffic caused by ‘minor incidents’, the statement added.

Ploughs have been fitted to gritters which were working into this morning to clear routes in the area, police and highways officials said.

Travel disruption to road and rail services is likely to continue in the warning areas, as well as the potential for accidents in icy places, the Met Office has said. 

As icy conditions persist, motorists were urged to stick to major roads that are most likely to have been gritted.

The UK Health Security Agency (UKHSA) extended its cold weather health alert for all of England until Sunday. 

Amber alerts have also been extended and will now run until January 12, meaning a rise in deaths is likely, the agency said.

Dr Agostinho Sousa, head of extreme events and health protection at the UKHSA, said: ‘We are extending the duration of our Cold-Health Alert, since the Met Office are forecasting that the low temperatures we are seeing will continue further into this week, with snow and icy conditions likely to persist.

‘This weather can have a serious impact on the health of some people, including those aged 65 and over and those with pre-existing health conditions, and it is therefore vital that we continue to check in on friends, family and neighbours that are most vulnerable.

‘These people could be more at risk of heart attacks, stroke and chest infections as a result of cold temperatures.’

The country has been hit by widespread flooding in recent days and a danger to life flood warning was issued for Barrow upon Soar in Leicestershire as firefighters had to rescue dozens of people stranded in rising water.