Britain's Prime Minister Theresa May attends the Welsh Conservative party conference at Llangollen, Wales, May 3, 2019. Britain's main Conservative and Labour parties took a hammering in local elections as Brexit-weary voters expressed frustration over the country's stalled departure from the European Union. AP

London -- Britain's main Conservative and Labour parties took a hammering in local elections as Brexit-weary voters expressed frustration over the country's stalled departure from the European Union. With results in from more than two-thirds of the 259 local authorities up for grabs, the governing Conservatives had lost more than 700 seats. The left-of-center opposition Labour Party, which had hoped to increase its tally of local councilors, lost 87.

The Conservatives had previously held about 60 percent of the more than 8,000 seats being contested across England and Northern Ireland. Elections are not being held in London, Scotland or Wales.

Get Breaking News Delivered to Your Inbox Click here to view related media. click to expand

Almost three years after Britain voted narrowly to quit the EU, both the date and terms of departure remain unclear amid political gridlock in Parliament.

Conservative Prime Minister Theresa May said the election results carried a "simple message" for both Conservatives and Labour: "Just get on and deliver Brexit."

Still divided

But the country is still split over leaving the EU; the rejection of both main parties reflected frustration from both pro-Brexit voters and supporters of Britain's EU membership.

Brexit extended until Oct. 31

"The people that voted to remain blame us for leaving and the people that voted to leave blame us because we haven't left yet," said Conservative politician Tim Warren, who lost his seat on Bath and North East Somerset Council in southwest England.

He said voters' mood was "almost anti-political ... I think they want to punish us for a lack of action in government."

Many Labour members blamed the party's poor showing on its ambivalent position on Brexit. The party supports the decision to leave the bloc - to the frustration of many Labour members and lawmakers, who are largely pro-EU - but opposes May's divorce deal.

Scottish Conservative leader Ruth Davidson said voters' message "seems to be 'a plague on both your houses' to the Conservatives and the Labour Party, who they see as a block on finding some sort of resolution to Brexit."

Pro-EU parties make gains

The biggest surge in votes went to the centrist, pro-EU Liberal Democrats, who gained more than 400 council seats. The Green Party, which is also against exiting the EU, and independents running on local issues also made gains.

"Voters have sent a clear message that they no longer have confidence in the Conservatives, but they are also refusing to reward Labour while the party prevaricates on the big issue of the day: Brexit," said Lib Dem leader Vince Cable.

Liberal Democrat Leader Vince Cable takes part in a question and answer session at the Liberal Democrat Party Conference at the Brighton Centre, September 16, 2018 in Brighton, England. Getty

The Conservatives and Labour are bracing for even worse results in European Parliament elections in three weeks.

Britain was due to have left the EU well before the European vote, but the departure has been delayed until Oct. 31 because Prime Minister Theresa May has been unable to get Parliament's backing for her divorce deal with the EU.

In those European elections on May 23, the main parties face additional opposition from new forces on the political scene - the anti-EU Brexit Party and the pro-European Change UK. Neither ran in Thursday's local elections.