The two main contenders to be Britain’s next prime minister are set to face off in a televised debate, with Conservative leader Rishi Sunak hoping to boost his party’s dismal outlook and Labour’s Keir Starmer aiming to cement his status as favourite.

The two-way leaders’ debate on Tuesday comes a day after populist Brexit-backer Nigel Farage dealt a blow to Sunak’s hopes of winning the July 4 election by announcing he will run for Parliament at the helm of the right-wing party Reform UK.

Farage kicked off his campaign on Tuesday in the eastern England seaside town of Clacton-on-Sea, where he visited a pub before a protester doused him in what appeared to be a milkshake. She was later arrested on suspicion of assault.

Farage is making an eighth attempt to win a seat in the House of Commons. His seven previous tries all failed.

The return of the populist politician, a key player in Britain’s 2016 decision to leave the European Union, is a major headache for Sunak’s party, which already trails Labour in opinion polls. Farage and Reform appear likely to siphon off votes of socially conservative older voters that the Tories have been targeting.

He claimed the Conservatives, who have been in office since 2010, had “betrayed” Brexit supporters because immigration had gone up, rather than down, since the United Kingdom left the EU.

Farage has injected volatility into an election that will almost certainly result in either Starmer or Sunak becoming Britain’s leader.

The two men will go head-to-head in a debate on broadcaster ITV, with Sunak likely to stress his stewardship of the economy, which has seen inflation fall to just over 2 percent from a peak of more than 11 percent in late 2022.

Starmer, whose main campaign refrain is the single word “change”, aims to persuade voters tired of the Tories that Labour can be trusted with the UK’s economy, borders and security.

Further debates are scheduled by other broadcasters before polling day, some featuring multiple party leaders and some with just the two frontrunners.

Sunak announced the election on May 22, calling it six months earlier than required and making an inauspicious start in a widely mocked rain-sodden speech outside 10 Downing Street.

A YouGov survey Monday – using the same nationwide modelling that correctly predicted the 2017 and 2019 general elections – showed Labour on track to win 422 of the 650 seats in Parliament.