By Joshua Kirby

British politician Nigel Farage said he is stepping down as a member of parliament and will refight a fresh election for his seat, a move he says aims to dispel allegations he broke financial-disclosure rules.

The leader of the anti-immigration party Reform UK, who is an ally of President Trump and who championed Britain's exit from the European Union, said in a broadcast Tuesday that he would stand down from his seat in the country's parliament. That would bring about a new election for the seat, which Farage said he will stand in.

The move comes after the ruling Labour Party asked the country's electoral authorities to investigate donations made to Farage in 2023 and 2024.

Farage's party has only a handful of seats in the U.K. parliament, but leads in many polls of voters and won hundreds of seats in local elections in May.

Write to Joshua Kirby at joshua.kirby@wsj.com; @joshualeokirby