Power suppliers said areas of London, the South East, Midlands and South West are without electricity.
Transport for London have confirmed that parts of the tube network, as well as some traffic lights have been impacted by the blackout.
The power cuts across the United Kingdom caused pandemonium as commuters attempted to get home for the weekend.
The UK is experiencing major power failures, with trains, airports and traffic lights having all been affected, the BBC reports.
In Cheshire, northwest England, police tweeted that they were aware of a power outage in the Ellesmere Port area.
London North Eastern Railway said all services were suspended in and out of King's Cross, one of London's busiest stations.
National Grid, which owns the electricity transmission system in England and Wales, said there had been "issues" with two power generators and the problems had now been resolved.
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'There was a power surge on the national grid this evening which means we lost power to all our signalling over a wide area, ' the spokesperson said.
Large parts of London and the South East are without electricity because of a widespread power cut this evening.
Road users were also affected by the power cut as traffic lights were also out of action.
"All trains were stopped while our back-up signalling system started up", she said.
"Some of the spaces in the airport have little daylight - we were literally plunged into darkness and people were using their phones as torches to see and get around". They said they are "aware of an unexpected issue affecting the above postcodes and are working hard to restore power by 1830".
Many Thameslink trains are also "at a stand" between London and Bedford.