Prime Minister Theresa May was confronted with anger from her own party after local election results which she admitted were "very difficult" for the Conservatives.
Backbench MPs called for her removal and warned that the party would be "toast" if it did not change direction, and a heckler interrupted the PM as she gave a speech in Wales, saying: "Why don't you resign? We don't want you."
Voters across the country vented frustrations over Brexit on both major parties, with the Liberal Democrats, Greens and independents benefiting from a hammering for both the Tories and Labour.
With the bulk of results from local elections in England declared, the Conservatives had shed more than 850 councillors and lost control of 33 authorities, with councils including Chelmsford, Winchester and Bath falling directly into the hands of the Lib Dems.
But Labour was also licking its wounds after forfeiting control in heartland councils like Burnley, Hartlepool and Bolsover.
Despite some predictions that Jeremy Corbyn's party could pick up three-figure gains, Labour was down more than 100 seats, though it did have the consolation of restoring control in Trafford for the first time sine 2003.
Both the Conservative and Labour high commands left no doubt that they saw the results as a demand for resolution of the Brexit impasse three years after the 2016 vote for EU withdrawal.
Mrs May told the Welsh Conservatives in Llangollen: "I think there was a simple message from yesterday's elections to both us and the Labour Party – 'Just get on and deliver Brexit'."
And shadow chancellor John McDonnell tweeted: "So far, message from local elections – 'Brexit – sort it'. Message received."
Heckler Stuart Davies, a Tory Party member and former county councillor, said he called for Mrs May to resign because of her handling of Brexit.
The 71-year-old, from Llangollen, told the Press Association: "I am furious at what she has done to our party. To put it bluntly, she is telling lies – 'We will be out by March 29'.
"I think I share the views of a lot of people who are party members. I did what I did because I know it was the right thing to do."
Remain-backing Labour MPs warned the leadership against striking a Brexit deal without the promise of a referendum, after shadow cabinet minister Barry Gardiner suggested the party was "bailing out" Tories in cross-party talks.
Ilford North MP Wes Streeting said: "Labour should not be bailing the Tories out. Any deal – any – must go to a public vote. Without a commitment to a public vote, I'll vote for a Labour-Tory deal when hell freezes over and I'm not alone in that."
There were calls from Tory MPs for Mrs May's removal as leader, with senior Brexiteer Sir Bernard Jenkin warning that the party would be "toast" unless it "mends its ways pretty quickly".
He said voters overwhelmingly believed that the Prime Minister had "lost the plot" and that the time had come for a change of leader.
"Certainly among Conservative activists and council candidates there is an almost universal feeling that it is time for her to move on," he said.
His comments were echoed by former Cabinet minister Priti Patel, who said voters saw Mrs May as "part of the problem".
"I just don't think we can continue like this. We need change, we need a change of leadership. Perhaps the time has now come for that," she told the BBC.
With results in from 202 of the 248 councils where elections were held, the Conservatives had lost 864 seats and Labour 110, while the Lib Dems had gained 494 and the Greens 121.
There were 174 more independent councillors, while Ukip lost 21.
Conservative Party chairman Brandon Lewis blamed the failure to resolve Brexit.
"People are frustrated with where they see parliamentarians are and the fact that we have found this impasse in Parliament," he said.
"It's a stark reminder to everybody in the House of Commons that we need to get past that impasse, deliver on what people voted for, and focus on that as parliamentarians as well."
The Conservatives lost councils including Peterborough, Basildon, Southend, Warwick and Worcester to no overall control, while Winchester, Chelmsford, Bath and North East Somerset, Somerset West and Taunton, Mole Valley, Vale of White Horse, Cotswold and Hinckley and Bosworth fell to the Liberal Democrats, with North Kesteven going to independents.
However the party held on in the bellwether council of Swindon, seen as a possible Labour gain, and took Walsall and North East Lincolnshire from no overall control.
Labour, meanwhile, lost control in Darlington, Middlesbrough, Stockton and Wirral and the mayoralty in Middlesbrough, where its vote was down 11% as independent Andy Preston was elected, although it did gain control of Amber Valley from Tories.
We'll see what final results of local elections look like by end of day as they are pretty mixed geographically up to now but so far message from local elections- "Brexit - sort it." Message received.
— John McDonnell MP (@johnmcdonnellMP) 3 May 2019
Even where the party held on in its traditional stronghold of Sunderland, which voted heavily for Brexit in the 2016 referendum, it still lost 10 council seats.
Council leader Graham Miller said the party had paid the price for its stance on Brexit, with some MPs calling for a second referendum.
"The people of Sunderland have said 'We are just not accepting that'. We have seen a massive protest vote on that issue tonight," he said.
Visiting Trafford to congratulate local activists, Mr Corbyn said the results were "interesting, to put it mildly".
"I wanted us to do better, of course," he said. "But I also say the swings to Labour in many parts of the country show that we can win seats in a general election, whenever that comes."
Polling expert Professor Sir John Curtice, of Strathclyde University, said the voters appeared to be punishing whichever of the main two parties was in control in their area.
"The Labour Party is losing where they are strong historically, the Conservatives are losing where they are strong historically. It's a plague on all your houses," he said.
In contrast, the Liberal Democrats, who fought on a pro-Remain platform, were in buoyant mood.
As well as picking up councils from the Tories, they took North Norfolk, Teignbridge and North Devon from no overall control.
On way to Chelmsford to celebrate best @libdems local election results in at least 15 years. In big cities and rural England - in both Leave and Remain areas - we have shown ourselves the strongest campaigning force and the big winners of the night. Three party politics is back.
— Vince Cable (@vincecable) 3 May 2019
Home affairs spokesman Sir Edward Davey said the results were "equivalent to our best strides forward ever in our history".
"We are clearly back in the game," he said. "The Liberal Democrats have proven we are that strong alternative to the Tories and Labour."
Green Party co-leader Jonathan Bartley said: "This is the biggest election night in our history. Greens are winning right across the country, and taking seats from a wide range of other parties.
"The Green message is clearly taking hold and can win anywhere."