Snow, wind and ice has continued to cause severe disruption as those who made it into work headed home ahead of a wintry weekend.
Drivers became stranded on several roads, while hundreds of flights and trains were cancelled.
And with the extreme weather already linked to a number of deaths, forecasters have warned the UK "is not out of the woods yet" - with a number of flood warnings in place.
ITV News Correspondent Rupert Evelyn looks ahead to the weekend's weather
On the roads, the South West and northern England experienced the worst driving conditions.
Road closures were in place on Friday evening on the A303 in southern England, the A1 in Northumberland and the transpennine routes of the M62, A628 and A66.
A Highways England spokeswoman said a collision involving between five and 10 vehicles occurred at 3.45pm on the A38 westbound between the A380 and the B3344.
Hertfordshire Police said around 100 cars were stuck on the A505 between Hitchin and Luton late on Friday.
A number of crashes were also reported on the M20 in Kent due to black ice.
On the trains operators complained of freezing rain and ice forming on the conductor rails that allow the trains to pick up power, and nearly all operators reported cancellations and delays.
Southeastern rail services were disrupted on Friday evening after passengers grew frustrated at delays near Lewisham, south London, and began walking down the tracks.
The rail operator called for passengers to remain onboard, saying it could only turn the power on when it was sure there was no one on the track.
Southeastern said it had cleared trespassers from the tracks and restored power by 10.15pm, allowing trains to move again, four hours after they became stranded.
Elsewhere, all cross-border trains between England and Scotland suspended on Friday and London Waterloo, the UK's busiest train station, closed at 8pm.
In one instance customers who set off on Thursday evening on board two South Western Railway trains were trapped for 12 hours before emergency services reached them.
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Airports were also badly hit, with more than 1,900 flights cancelled to or from UK and Irish airports on Friday.
Heathrow, the world's busiest two-runway airport, saw at least 370 departing or arriving flights cancelled, representing around 30% of all scheduled services.
Dublin Airport was forced to close, leading to 342 cancellations, while Edinburgh saw 219 flights unable to operate.
Other airports that saw disruption include: Glasgow International, Bristol, London City, Manchester, Cork, London Gatwick, Birmingham and Newcastle.
More than 5,400 flights have been cancelled to or from European airports since Wednesday, meaning many UK travellers are now stranded abroad.
The Army was called in overnight on Thursday to help evacuate trapped drivers in Hampshire and Somerset as emergency services found themselves overwhelmed.
In Scotland, the military were also used to help transport NHS staff in Edinburgh to and from work.
An MoD spokesman said: "The MoD helps in cases of extreme weather when we receive a request from our civilian authority colleagues.
"There are three UK standby battalions held at high readiness to respond to UK contingencies and emergencies, including support to local authorities."
A number of deaths have also been reported related to the freezing conditions, including a homeless man who was found dead on Friday after sleeping rough in tent.
Two teenage boys were also seriously injured after high winds left them trapped under a fallen tree in Blackley, north Manchester, requiring firefighters to prize them free.
Meanwhile, the extreme weather has seen health boards cancel non-essential operations and outpatient appointments on Friday, while NHS 24 has described its operations as being "stretched".
Thousands of homes continue to be without power with high winds and snow hampering repair work, with yellow warnings for snow still in place for much of Scotland and expected to remain up until 11.55pm on Saturday.
In Ireland, an estimated 10,000 people have been left without phone and internet access.
EIR said the severe weather has caused damage to its pole, cable and mast infrastructure, knocking out access to broadband, telephone and mobile service.
Co Limerick has been worst hit with 7,000 customers left without services in the areas of Hospital, Pallasgreen, Murroe, Croom and Kilfinane.
Prime Minister Theresa May has thanked the emergency services for keeping "vital public services going" during the extreme weather.
NHS England chief executive Simon Stevens praised NHS staff for ensuring patient care has continued despite the weather conditions.
He said: "In these adverse circumstances NHS staff have taken extraordinary measures to get into work and look after patients.
"Once again the NHS is showing that we are there for people when they need us and that's all down to our staff, so a huge thank you to everybody across the NHS who is going the extra mile for people at this highly pressurised time."