(Bloomberg) -- Prime Minister Theresa May gave a steadfast defense of her plans for Britain’s departure from the European Union ahead of key talks this week, while admitting to feeling “irritated” at speculation building within her Conservative Party about a potential leadership challenge.

European leaders gather in Salzburg, Austria, on Wednesday to try to advance Brexit negotiations, which are stalled over how to avoid a hard border with Ireland after Britain leaves. The most ardent Brexiteers in May’s party have called on her to drop her proposal, thrashed out with the Cabinet at her Chequers retreat in July, to ensure a frictionless border by keeping Britain closely tied to EU trade rules.

“The only proposal that’s been put forward that delivers on them not having a hard border and ensures that we don’t carve up the United Kingdom, is the Chequers Plan,” May told the BBC, according to excerpts of the interview released ahead of its full broadcast on Monday.

But a “chuck Chequers” movement is gathering momentum among euroskeptic Tories, and rumors continue to swirl about a formal attempt to oust May if she doesn’t back down. Former Foreign Secretary Boris Johnson, the favorite in surveys of Tory party members to succeed May, has likened her Brexit approach to strapping on a suicide vest and handing Brussels the detonator.

‘Bit Irritated’

“This is where I get a little bit irritated,” May told the BBC. “This debate is not about my future, this debate is about the future of the people of the U.K. and the future of the United Kingdom,” she said, adding that Johnson’s language was “completely inappropriate.”

May appeared to embrace former Chancellor of the Exchequer Ken Clarke’s famous description of her as a “bloody difficult” woman, telling the BBC that person is “still there” and that it’s a trait she’s prepared to use when needed.

“There’s a difference between those who think you can only be bloody difficult in public, and those who think actually you bide your time, and you’re bloody difficult when the time is right -- and when it really matters,” she said.

To contact the reporter on this story: Stuart Biggs in London at sbiggs3@bloomberg.net

To contact the editors responsible for this story: Flavia Krause-Jackson at fjackson@bloomberg.net, Steve Geimann

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