The vote is the first big test of Rishi Sunak's popularity, since becoming prime minister.
ADVERTISEMENTBritain's ruling Conservatives have suffered sweeping losses in local elections, results show.
The left-of-centre Labour Party, Greens and Liberal Democrats have gained at their expense, with around half of councils in England declared so far.
More results from key battlegrounds are expected this afternoon.
In the UK, councils are responsible for services like transport, housing, education, social care, waste collection and libraries. They often command billion-pound budgets and can exert a significant influence on their local area.
Thursday's vote is seen as a litmus test for the Conservatives, who have been in power for 13 years.
Several issues have dented their support in recent years, from economic mismanagement to sewage dumping, though they have not been hit as badly as some expected.
Pundits believe today's results show Labour are on course for a general election victory, though we cannot say for sure.
Labour's national campaign coordinator Shabana Mahmood told the BBC her party was succeeding because it was focusing on the "number one issue facing voters - the cost of living crisis."
"It is early days but it is a very strong set of results... and it shows that we're on course for a majority Labour government at the next general election," she said.
Labour took control of key councils it was targeting, such as Plymouth, a large navy city in the southwest, Stoke-on-Trent, Medway and East Staffordshire.
Meanwhile, the Conservatives lost control of councils around the country, including Tamworth, Brentwood, Hertsmere and NW Leicestershire.
Greg Hands, Chairman of the Conservatives, called the "results" disappointing, but insisted there was no "enthusiasm" for the Labour leader, Sir Keir Starmer.
"Some excellent Conservative councillors have lost their seats, so it's not been a good night overall for us," he told BBC Breakfast.
The full picture will not become clear until Friday afternoon, with 230 of England's 317 councils conducting elections.
However, the Liberal Democrats have had a strong showing so far, whiles the anti-Brexit party hopes to seize key Conservative heartlands in the south of England.
Party leader Sir Ed Davey hailed their performance as "ground-breaking".
The Green are also pleased with the results, saying they expect "significant gains" later in the day.
Despite losing control of several councils, PM Sunak has acknowledged some "disappointing" results, but insisted the Tories are making progress in "key election battlegrounds".
ADVERTISEMENTEarlier today, he said: "I’m not detecting any massive groundswell of movement towards the Labour Party or excitement for their agenda."
All councils are expected to declare by 8 p.m. on Friday.
It was the first election in the country where voters needed to show a photo ID.
The Electoral Commission said the new rules meant some people were turned away, with experts warning Euronews in March Britain was "gambling with its democracy".