A massive power cut plunged a large part of Lincolnshire into darkness, leaving 95,000 homes without electricity.
The lights went out just before 4.25pm.
Lincoln and a number of surrounding villages, plus areas as far afield as Retford and Worksop in neighbouring Nottinghamshire were without power.
A spokesman for Western Power Distribution said: “Our engineers in Lincoln said the problem was with the supergrid at West Burton Power Station between Gainsborough and Retford.
“We can’t say exactly how many customers are affected, but we are working towards restoring power to all our customers as soon as possible.”
What caused the exact problem with the supergrid is unknown. It was hoped power would be restored to most homes by 8pm, though customers have been warned the power may go on and off again as engineers work on the problem.
Traffic lights were out by the New Life Church in Newland and police are directing queuing traffic.
High Street in Lincoln was also left without power.
John Clulow, from Maltby, near Horncastle, said: “I was in Waterstones coming down the stairs when the lights went off and everyone stood still.
“Everyone was calm. I think somebody said the ATMs had stopped working. I walked outside and some lady had fallen down by the steps.”
Tammy Simpson, assistant manager at Ruddocks, said: “It literally all went black apart from the security lights.
“There were about 20 to 30 people in here and a lot of people at the tills.
“Every was a bit shaken and shocked but people remained calm.”
Maxine Derbyshire, from Barnsley, was in Lincoln visiting her daughter and grandson when she was caught up in the blackout.
“I was walking across the railway crossing in High Street before going up to the Christmas Market when all the lights went out,” she said.
“I just couldn’t see anything, then everyone who was standing around started using their mobile phones as torches.
“I lost my husband along the way and I went off to look for him.”
Watch a video of the power cut in Lincoln's High Street and Cornhill here.