The UK's coalition parties have suffered heavy defeats in local elections in England and Wales.
Key councils such as Thurrock, Harlow, Southampton, Birmingham, Norwich, Great Yarmouth and Chorley fell to Ed Miliband’s party.
Prime Minister David Cameron was also embarrassed by losses in his Oxfordshire constituency – with Labour taking the seats of Witney Central, Witney East and Chipping Norton.
In a further blow, Manchester, Nottingham and Coventry ignored Mr Cameron’s pleas and rejected proposals for elected mayors. Birmingham and other cities are expected to follow suit.
The Liberal Democrats were not spared pain, being left without a representative on several powerful councils as voters seemingly punished the Government for austerity measures.
Overall Labour looked on track to exceed the 700 gains experts had set as the threshold for a good performance.
A BBC projection of the national vote share gave the party 39% – up three points on a year ago. The Tories were down four on 31% and the Lib Dems trod water on 16%.
However, Mr Miliband did suffer a setback in Bradford, where his party lost seats to Respect.
The results followed George Galloway’s shock success in last month’s parliamentary by-election.
Tories pointed to a low turnout, estimated at little over 30%, suggesting that “apathy” had played a significant part in the results.
But there were also calls for a change in direction from the leadership. Senior backbencher Bernard Jenkin insisted the party had to focus on the economy rather than allowing their Lib Dem coalition partners to dictate the agenda.
“The coalition is going to look completely stupid if it follow through on Lords reform,” he told the BBC.
Local Government Secretary and former Tory chairman Eric Pickles told Sky News the outcome was to be expected.
He said: “When a party is rock bottom there’s only one way to go. But I’m not seeking to rain on Labour’s parade.”
Shadow justice minister Sadiq Khan said: “It has been a good night for Labour because people who have been concerned about some of the decisions of this coalition Government are punishing them by voting for Labour candidates all around the country.
“But we mustn’t be complacent or smug about this.”
Some 5,000 seats were at stake on 181 local councils across England, Scotland and Wales.
Most were last up for grabs in 2008, when the Conservatives made significant gains and Labour and the Lib Dems were hit hard.
Around 1,200 are in Scotland – where Labour is expected to find it tougher to make inroads against the SNP – and yet to be counted.
Labour gained Plymouth from the Tories and Reading from no overall control as it sought to re-establish itself in crucial electoral battlegrounds.
The party won four seats to strip the Lib Dems of control in Cambridge.
A Labour source said: “We are making real progress in areas where we need to win (at the general election) in 2015.”
The remainder of the 10 cities holding referendums on elected mayors will reveal their results later.
And the Prime Minister will be hoping that Boris Johnson has bucked the trend by securing re-election as London Mayor.
An eve-of-poll survey for the Evening Standard suggested that Mr Johnson is set for victory over Labour’s Ken Livingstone, by a margin of 53% to 47%.
A Labour source said: “These are strong results for Labour.
“A clear win on national share of the vote – best local election result for Labour since 1997.
“Taking councils no-one expected us to – Great Yarmouth and Dudley. Winning councils in the South – Southampton and Plymouth.
“Winning in areas as where there are currently no Labour MPs – Harlow and Thurrock.”