LONDON: A live debate between the two candidates vying to succeed Boris Johnson as British prime minister came to a dramatic end on Tuesday when the presenter fainted.

Foreign Secretary Liz Truss, the bookmakers' favourite to win the Conservative Party leadership election, and former finance minister Rishi Sunak had been sparring over their plans for about 30 minutes when there was a loud crash in the studio.

It occurred while the camera was on Truss in the debate hosted by Talk TV and the Sun newspaper. Truss held her hands to her face and said, "Oh my God", and the broadcast was then cut.

Talk TV said the presenter, Kate McCann, had fainted.

"Although she is fine, the medical advice was that we shouldn't continue with the debate. We apologise to our viewers and listeners," Talk TV said on Twitter.

Both Truss and Sunak later sent messages on Twitter wishing McCann well.

"Relieved to hear @KateEMcCann is fine. Really sorry that such a good debate had to end," Truss said.

Before the premature end, Truss and Sunak had again clashed over their tax and spending plans and what they would do to address a cost of living crisis, in what has become an increasingly hostile competition to become prime minister.

Truss says Sunak's emphasis on balancing the government's books and raising tax on business would tip the economy into recession.

"I do think it is morally wrong at this moment when families are struggling to pay for their food, that we have put up taxes on ordinary people when we said we wouldn't in our manifesto and when we didn't need to do so," Truss said.

Sunak, whose resignation from government earlier this month set in motion Johnson's downfall, argued that money from tax rises he brought in was necessary to pay for extra spending on healthcare.

"I think what's morally wrong is asking our children and grandchildren to pick up the tab for the bills that we're not prepared to meet," Sunak said.

Tuesday's debate was the second head-to-head tussle between the two contenders.

A YouGov poll of Conservative Party members, who will ultimately decide on the next leader, found 50% thought Truss performed the best in the first clash on Monday, with 39% backing Sunak.

They also saw Truss as more in touch with ordinary people, more likeable and more trustworthy. Sunak narrowly edged her by 43% to 42% on who was the most prime ministerial.

The winner of the election, which will be decided by a ballot of the fewer than 200,000 Conservative members, will be announced on Sept. 5.