Liberal Democrat deputy leader Simon Hughes has confirmed the party will field candidates against the Tories at the next general election.
As the coalition government prepares to mark its first 100 days, he said there would be no electoral pact despite the two parties working together.
He told the BBC the coalition was a business arrangement, not a marriage.
"You fight the election on your own and we will do it because we want to win more seats," he said.
"We want to have more influence and we want to be in government ideally on our own because evidently if we have a majority we can implement more of our policies and not only a proportion."
Mr Hughes said the party's constitution would not allow a pact as it states that every voter at a general election must have the opportunity to vote for a Lib Dem candidate.
"We couldn't change that without the party changing its constitution and that requires more than a 50% majority and I can't envision that will happen."
Since the coalition was formed in May, poll ratings for the Lib Dems have slipped.
But Mr Hughes said he was not surprised as the "prime minister who is a Conservative is seen to be leading and we're the junior partners".
"I'm not troubled about that in the long term," he said.
"Our job now is to let people know firstly what we have added to government; what has changed in government because we are there but also the distinctive things that make it worth voting for Liberal Democrats."