Britain’s populist, anti-immigration party Reform UK has beaten Labour by a tiny margin in a by-election, dealing the government a mid-term setback and ruffling the country’s historically resilient two-party hegemony.

Britain's right-wing Reform UK party won a vacant parliamentary seat, two mayoralties and control of several councils on Friday in early results from elections that its leader Nigel Farage said proved it was now the real opposition.

Reform UK's victory in the Runcorn and Helsby by-election has been hailed by the party's newest MP. Former Conservative councillor Sarah Pochin dramatically edged out Labour's Kar