LONDON — Zia Yusuf dramatically resigned as chairman of the resurgent Reform UK party on Thursday in a bitter blow to leader Nigel Farage.

Yusuf, who took the key job days after the 2024 general election, announced his resignation in a post on the social media website X, hours after wading into a dispute about the party’s policy towards the burqa.

“I no longer believe working to get a Reform government elected is a good use of my time, and hereby resign the office,” he said.

Yusuf had earlier criticized the party’s new MP Sarah Pochin for asking Prime Minister Keir Starmer whether the U.K. would ban the burqa in a House of Commons exchange on Wednesday.

“Nothing to do with me,” Yusuf said Thursday morning about the Pochin question.

Yusuf, the co-founder of concierge service Velocity Black, was seen as a crucial hire for Reform as Farage attempted to professionalize his movement. The departure will be seen as a setback to the party’s plans for electoral success.

“I’ve worked full time as a volunteer to take the party from 14 to 30 percent, quadrupled its membership and delivered historic electoral results,” Yusuf wrote in his X post.

Farage quickly posted that he was “genuinely sorry” about Yusuf’s abrupt departure, praising the ex-chairman for being a “huge factor in our success.”

“Politics can be a highly pressured and difficult game and Zia has clearly had enough,” Farage added.

Reform UK is currently polling in first place at 30 percent — seven percentage points ahead of the ruling Labour Party, according to POLITICO’s poll of polls.

Last month, Reform UK won more than 600 councilors at the local elections and took the Runcorn and Helsby constituency from Labour in a by-election. Farage has claimed Reform can replace the Tories as the party of the right and has the potential to enter government.

Yusuf’s departure comes after another key figure, the MP Rupert Lowe, was suspended from the party in March amid claims of threats towards Yusuf (which Lowe denied.) Lowe has since said Farage must never become prime minister.

In May, the Crown Prosecution Service said Lowe would not face any criminal charges.