Brexit Party MEP Ann Widdecombe said she "yearns for her P45", as Boris Johnson pledged to deliver Brexit by January 31.
Ms Widdecombe, who represents South West England in the European Parliament, told talkRADIO her party would work tirelessly to ensure Mr Johnson delivered on his promise.
"Our job now is very straightforward - to make sure we get a proper Brexit and not a fudge," she said.
"I think the temptation is to say 'Well, Boris says he’s going to deliver Brexit so let him get on with it', but we need to make sure that what he delivers actually is Brexit."
She continued: "I’m longing to be without that job in the European Parliament, I’ve never yearned for my P45 so earnestly in my life."
Her comments come after the Brexit Party failed to secure any seats at the general election, despite party leader Nigel Farage insisting they would put their "total effort" into contesting seats held by the Labour Party and "Remainer parties".
Ms Widdecombe was defeated by Labour's Luke Pollard at the polls, who has been re-elected as the MP for Plymouth Sutton and Devonport.
The Conservative Party secured their largest majority since 1987 in the election, taking a number of seats from Labour in Brexit-backing areas across the North, Midlands and Wales.
In his victory speech after retaining his own seat, Uxbridge and South Ruislip, Boris Johnson claimed the party had a "powerful new mandate to get Brexit done".
Ms Widdecombe added: "The first priority has got to be to get Brexit done and by that I mean a proper Brexit, and not half in, half out. We must concentrate very heavily over the next few months on making sure the public know exactly what is going on."
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