The British party has won just one seat at local elections
The leader of the UK Independence Party (UKIP) says the party has been "a victim of its own success" over Brexit.
Paul Nuttall says his party was prepared to pay the price of losing seats in British local elections because it had won the crucial EU referendum.
UK voters went to the polls Thursday to decide the make up of 88 councils in England, Scotland and Wales - and for the first time picking new 'metro mayors' for six large urban areas.
With 31 of 34 results in, the Conservatives had an extra 307 councillors in England and control of another 10 local authorities.
Many of these council gains came at the expense of UKIP, whose vote has collapsed.
The party won just one seat, down 133.
Labour was down 150 seats and lost control of one council.
Labour also suffered a painful defeat in Glasgow, where it lost sway over the city council, under its control since 1980.
It also lost Welsh councils Blaenau Gwent and Merthyr Tydfil to independents, as well as Bridgend.
But Jeremy Corbyn's party did win mayoral contests in Doncaster, North Tyneside, Liverpool and in Greater Manchester, where former health secretary Andy Burnham was elected with more than 60% of the vote.
Mr Corbyn told supporters in Liverpool that there had been "some difficult results" overnight, but added: "Some have been very good. We've gained seats in some places, we've held councils that many people predicted we wouldn't."
The Liberal Democrats performance was mixed, coming away with 273 council seats - down 26 overall.
It failed to break through against the Conservatives in southwest England but in some general election target seats, such as Eastleigh and Wells, it made gains.
Leader Tim Farron told supporters his party was now "breathing down Labour's necks" but warned that Prime Minister Theresa May was still heading for a "coronation" in the general election.
In Scotland, Conservative leader Ruth Davidson said only her party could lead the "fightback against the SNP" - who want another independence referendum.
The Tories were up on 276 seats, up 164.
For the first time, the party had a councillor elected in the most deprived areas of Scotland, Paisley's Ferguslie Park.
Labour emerged seriously diminished, losing five councils and with 133 fewer councillors.
The SNP had 431 seats across Scotland, down seven.
Party leader Nicola Sturgeon said wresting control from Labour and becoming the biggest party on Glasgow City Council was a "fantastic, historic result".
The SNP won 39 out of 85 seats, just four short of an outright majority, as Labour went from 41 to 31.
Ms Sturgeon said: "What we've seen across Scotland today of course is the SNP vote holding firm... What we've seen is the collapse of Labour and that's the reason for the increase in the Conservative vote."
In Wales, the Tories gained 80 councillors and added control of one authority. Plaid Cymru gained 32 councillors, with 202 in all.
Labour lost over 100 councillors, but held on to councils in Cardiff and Swansea.