Mr Farage said he was looking forward to the contest
UKIP leader Nigel Farage is to stand against Commons Speaker John Bercow at the next general election.
Mr Farage told the BBC he was standing because MPs "have broken the trust" of the British people and Mr Bercow "represents the worst" of the Commons.
Convention rules that Speakers stay out of party politics. Labour and the Lib Dems will not stand against Mr Bercow in his Buckingham constituency.
Mr Bercow said he was "more than happy" to be judged on his record as an MP.
He was returned as Conservative MP for Buckingham, which he has represented since 1997, with a majority of 18,000 at the last general election.
Mr Farage, speaking as UKIP's annual conference got under way at Southport, Merseyside, said he had chosen to stand against the Speaker for a number of reasons.
While Mr Bercow had himself been "embroiled" in the expenses row earlier this year, Mr Farage said he was also the "symbolic" head of a Parliament which had ceded powers to Brussels.
"Everything from what light bulbs we can put in our living room to how we regulate hedge funds is decided in Brussels and the Speaker does not intend to reverse that.
"I want the election in Buckingham to be a debate about how we are governed in this country."
The Daily Telegraph said Mr Bercow had changed the designation of his second home - a practice known as flipping - to maximise his allowance claims but the MP said the moves were due to changes in family circumstances.
Mr Bercow, who was elected Speaker in June, said in a statement: "I am more than happy to be judged on my track record over 12 years as MP for Buckingham, my continuing commitment to the constituency and my determination to restore faith in Parliament."
BBC political correspondent Laura Kuenssberg said it was "looking like being a very lively race indeed".
The convention is that none of the large Westminster parties stand against a Speaker at a general election, although the Scottish National Party put up a candidate against Michael Martin in 2005.
UKIP, which wants the UK to withdraw from the EU, came second in June's European elections, taking 13 seats.
The party is using its conference, which runs until Saturday, to discuss its tactics for the general election, which must be held by next June.
In two conference speeches on Friday and Saturday, Mr Farage will urge the UKIP to build on its performances and delegates will also debate issues including the abolition of ID cards, the economic crisis and immigration.
Another motion to be put to conference calls for people to withhold the TV licence fee until the BBC does more to "acknowledge UKIP as the fourth party" at the next general election.
UKIP recently set up a 30-member European Parliament grouping called Europe of Freedom and Democracy.