Ukip leader Paul Nuttall will fight the crunch Stoke-on-Trent Central by-election in a major test of his plan to replace Labour as the party of the working class in the Midlands and the North of England.
Mr Nuttall was confirmed as the candidate after the other 10 people on the shortlist withdrew from the contest to make way for their leader.
His decision to stand indicates Ukip's belief that it has a strong chance of taking the former Labour stronghold on February 23.
Nr Nuttall will be seeking the support of some of the 65.7% of Stoke voters who backed Leave in last year's EU referendum, describing the city as "the capital of Brexit".
He sought to exploit Labour divisions over the vote to trigger Article 50 of the EU treaties to start the exit process, and accused Jeremy Corbyn's party of trying to "water down Brexit".
Addressing the local party, he said: "In the referendum last year just about 70% of voters from Stoke voted to leave the European Union.
"This was the highest vote share for Leave in any city in the United Kingdom.
"That makes Stoke the capital of Brexit.
"And be clear - nobody will fight harder than me to ensure that Brexit happens in full and good time.
"If I am elected as your MP it will send a signal to all those who are trying to put spanners in the works that their jobs are on the line.
"And in particular those Labour MPs who represent working class communities which voted Leave and now want to water down Brexit.
"They will be put on notice that if they seek to frustrate the will of the people they may as well be asking for their P45s in the post."
Pitching himself as the anti-establishment candidate, Mr Nuttall attacked the "metropolitan elite" at the top of the Labour Party and said he could give constituents a national voice as a party leader.
"The metropolitan elite has had the fate of working people in its grip for too long," he said..
"It's now time that that grip was broken.
"I have heard people say that these communities have been left behind, this is no doubt true.
"But it is a phrase that I do not like.
"I prefer to say that these communities have been let down, and let down time and time again.
"Let down by a haughty political establishment that looks down its nose at working class people, let down by a Labour Party in particular that takes their votes for granted."