LONDON Britain's opposition Labour Party won a parliamentary seat in northern England on Friday, inflicting a heavy loss on the governing Conservatives at the start of what looked set to be a bruising round of results for Prime Minister Rishi Sunak.

The thumping victory set the tone for what will be a closely watched two days of local results before a national election this year, which polling shows could put Labour leader Keir Starmer in power and end 14 years of Conservative government.

Voters cast their ballots on Thursday for more than 2,000 seats on local authorities across England and a handful of high-profile mayoral elections, including in the capital London.

Blackpool South was the only parliamentary seat up for grabs after the incumbent, elected in 2019 as a Conservative candidate, quit over a lobbying scandal.

Labour candidate Chris Webb won the Blackpool election with 10,825 votes. The Conservative candidate came in second with 3,218. The swing of 26% to Labour from the 2019 result was the third biggest in post-war by-election history, polling expert John Curtice said.

The defeat in Blackpool and early signs of deep losses at the council level will boost Labour's hopes for a sweeping victory over Sunak's Conservatives in the national election.

"This seismic win in Blackpool South is the most important result today," Starmer said.

"This is the one contest where voters had the chance to send a message to Rishi Sunak’s Conservatives directly, and that message is an overwhelming vote for change."

Poor showing by conservatives

Sunak's Conservatives are about 20 percentage points behind Labour in most opinion polls for the national election, which Sunak intends to call in the second half of the year.

Curtice said that based on results so far, the Conservatives could be looking at their worst local election results for 40 years and were on course for defeat in the national election.

The first 500 of the more than 2,600 local council results showed Labour making gains at the expense of the Conservatives - in line with finance minister Jeremy Hunt's pre-vote prediction of significant losses for the governing party.

The Conservatives seized on results in one southeastern council that Starmer had made a key target, but failed to win control of.

"While this is a tough night for the Conservative party, it's clear there is absolutely no love for Keir Starmer," a Conservative spokesperson said.

Although local elections do not always reflect how people will vote in a national contest, a heavy defeat could trigger renewed anger in the Conservative Party over Sunak's leadership and the prospect of losing power.

The extent of that unrest could hinge on the results of two mayoral elections in which the Conservatives hope to show they can still hold ground in central and northeast England.

The Tees Valley mayoral result is due on Friday, while the West Midlands mayor is to be announced on Saturday. The result in London, where current Labour mayor Sadiq Khan is expected to win another term, is also due on Saturday.

  - Reuters