The Conservative Party has suffered heavy losses in Rishi Sunak's first electoral test as prime minister.
Labour took Medway off the Tories and will run the Kent council for the first time since 1998.
And in West Devon, Conservatives lost two councillors to the Greens.
After Thursday's local elections, Labour believe results suggest Keir Starmer will be able to replace Mr Sunak in No 10.
The Liberal Democrats also made gains as the Tories lost control of a series of councils across England.
Labour gained control of Plymouth — a result branded “terrible” by government minister and local politician Johnny Mercer — then did the same in Stoke-on-Trent.
Labour leader Keir Starmer said the results suggested his party is on course for a majority at the next general election.
To the cheers of Labour activists in Medway, Mr Starmer said: "You didn't just get it over the line, you blew the doors off."
He said there have been "fantastic results across the country" in "battlegrounds" and "places we need to win", citing victories in Plymouth, Stoke and Middlesbrough.
"And make no no mistake, we are on course for a Labour majority at the next general election.
"We've changed our party. We've won the trust, the confidence, of voters, and now we can go on to change our country. Change is possible. A better Britain is possible," he said.
Early on Friday as the results continued to trickle in, Mr Sunak said: "The message I am hearing is people want us to focus on their priorities and they want us to deliver for them.
"That's about halving inflation, growing the economy, reducing debt, cutting waiting lists and stopping the boats.
"That's what people care about. That's what they want us to deliver. And that's what I and the government are going to work very hard to do."
The Conservative Party Chairman Greg Hands said the party predicted it would be a "difficult night".
He told Radio 4: "That has turned out to be the case. We have lost some well-run Conservative councils, some good Conservative councillors. So clearly overall it's a disappointing night for the party and for the government."
In Hertsmere, where Deputy Prime Minister Oliver Dowden is MP, the Tories lost control of the council, with 13 councillors voted out while Labour gained seven and the Liberal Democrats six.
Tamworth, Brentford and north-west Leicestershire fell from Conservative administrations to no overall control and Labour replaced them as the largest party in Hartlepool and Worcester.
West Lindsey remained under no overall control but the Lib Dems replaced the Tories as the largest party.
Liberal Democrat Leader Sir Ed Davey said they were groundbreaking results for his party that were "exceeding all expectations".
He told Radio 4's Today show on Friday: "Just before I came on air I was told we took control of the Royal Borough of Windsor and Maidenhead.
"Across the country we have been beating the Conservatives. And I think it is going to get worse [for the party]. They have just started counting I am told in places like Surrey and Sussex, Hertfordshire and Oxfordshire, across what I would christen the blue wall.
"So yes, I have got a smile on my face."
Senior Conservatives are trying to present the setbacks as a midterm blip, but with the prospect of a general election in 2024 there will be concerns that they have suffered losses in the north, south and the Midlands.
In Boston, the Tories lost 10 councillors in the Lincolnshire town they had run as a minority, with independents now taking the majority of seats.
With full results from 53 of the 230 councils where elections were being held:
- The Tories have lost five councils and suffered a net loss of 137 councillors.
- Labour has gained control of two councils and had 111 councillors elected.
- The Liberal Democrats have a net gain of 43 councillors.
- The Green Party has gained nine councillors.
More than 8,000 council seats were up for election on Thursday in 230 local authorities, while mayors were being chosen in Bedford, Leicester, Mansfield and Middlesbrough.
The last time the same council seats were contested was in May 2019, when the Tories performed poorly under former prime minister Theresa May as she struggled with Brexit.
In those elections they lost more than 1,300 council seats and majority political control of 44 councils, meaning they have less to lose this time than they might have done.
The votes will continue to be counted on Friday.
Conservatives could lose more than 1,000 seats
The Tories have sought to manage expectations by pointing to forecasts which suggest they could lose more than 1,000 seats if things go badly.
The party will seek to portray any defeat below that scale as better than expected — although the loss of hundreds of councillors will not help morale within the Conservative ranks.
Northern Ireland Secretary Chris Heaton-Harris said the party had experienced a "bit of a blip" following the turmoil in No 10 during which Boris Johnson and Liz Truss were ousted before Mr Sunak took office.
He attempted to present the expected losses as mid-term blues for the Tories, telling Sky News: "The British people are a very sensible group of folk and they understand what's important.
"Occasionally they like to give political parties a bit of a reminder of who the politicians serve. Certainly when you get into being mid-term in a government you get quite a bit of that."
Veterans Minister Mr Mercer told the BBC the Plymouth result was due to local factors and insisted that the prime minister was "the sort of strong leader this country needs at this time".
The council's decision to fell dozens of trees in the city centre contributed to the loss of Tory support.
Mr Mercer said: "I think, locally, it has been very difficult. The Conservative group here has been through a very difficult time. We have seen that reflected on the doors, in the campaign, and we have seen that reflected in the results tonight. But, you know, we take it on the chin."
Stoke-on-Trent North's Tory MP Jonathan Gullis told Sky News that councillors had "suffered because at the end of 2022, the Conservative Party as a brand was certainly damaged".
In Tamworth ― the seat of scandal-hit former Tory whip Chris Pincher ― Labour made seven gains, pushing it from Conservative into no overall control.
But in Hull, Labour's attempts to regain the council from the Liberal Democrats failed, with Sir Ed Davey's party tightening its grip on the authority.
Labour’s Chris Cooke won the battle to become mayor of Middlesbrough, defeating the independent incumbent Andy Preston with a swing of almost 20 per cent, a result the party said was “beyond our expectations” and “exactly the kind of progress we needed to make in Teesside”.
Labour claimed that, based on the aggregate vote, the party would have won the Westminster constituencies of Hartlepool, Stevenage, Dudley South, Ipswich, West Bromwich East, Great Grimsby and Aldershot, which have been held by the Tories since its creation as a seat in 1918.
“Tory MPs will be very worried,” a Labour source said.
“This is supposed to be Rishi Sunak’s political honeymoon, but on these results they would have lost a bunch of seats — including one they’ve held for over 100 years.”
Campaigners say thousands of people were denied their right to vote due to the new stipulation that voters have to present photo ID, and branded the elections a “dark day for British democracy”.
But Mr Heaton-Harris insisted the policy was a “thoroughly good thing” even though the elections watchdog said some people had been turned away from polling stations.
“We already know from our research that the ID requirement posed a greater challenge for some groups in society, and that some people were regrettably unable to vote today as a result,” an Electoral Commission spokesman said.
“It will be essential to understand the extent of this impact, and the reasons behind it, before a final view can be taken on how the policy has worked in practice and what can be learnt for future elections.”
Tom Brake of Unlock Democracy, who is leading a coalition of groups opposed to the policy including the Electoral Reform Society, Fair Vote UK and Open Britain, said: “Today has been a dark day for British democracy.
“Reports from all over the country confirm our very worst fears of the impact of the disastrous policy which has been made worse by the shambolic way it has been introduced.”
The Association of Electoral Administrators’ chief executive Peter Stanyon said there had been “many anecdotal reports” of people being unable to vote but “it is still too early to gauge how introducing voter ID has gone”.
The results of the elections will be keenly studied with the prospect of a general election in 2024.
