A keynote speech by Lib Dem leader Sir Menzies Campbell has been overshadowed by speculation over his strategy in the event of a future hung Parliament.
In his speech to the party's spring conference he set out "five tests" for a Gordon Brown-led government.
A party official suggested it was the first indication Sir Menzies would be interested in forming a coalition if the Lib Dems held the balance of power.
Ed Davey, Sir Menzies' chief of staff, said the briefing was "unauthorised".
"The tests Ming set for Brown were about his likely government in a few months' time and not about some post-election situation," he said.
Sir Menzies told delegates in Harrogate that meeting the tests would show whether Mr Brown - widely expected top succeed Tony Blair as prime minister this year - could offer a "change of direction".
The conference marked Sir Menzies first year as leader
He called on the chancellor to "end Labour's authoritarian attack on civil liberties" by scrapping ID cards.
He urged him to "grasp the challenge posed by climate change" and, thirdly, "break open the poverty trap".
His fourth test was to "trust the people" by devolving power to local people and the fifth was that "Britain's foreign policy should not be set in Washington".
If Mr Brown met these tests, he would have embraced liberal democracy, Sir Menzies told delegates.
He said: "Britain needs a government that is prepared to reduce inequality and provide quality public services throughout the whole of Britain.
"To uphold the rule of law and to preserve our traditional freedoms, to take on the challenge of climate change and to restore Britain's international reputation.
"The question is - can Gordon Brown meet that challenge? Does he have the courage to take Britain in a new direction?"
Opinion polls point strongly towards a hung parliament at the next election, with the Liberal Democrats potentially holding the balance of power.
In an apparent policy shift, the sticking point of proportional representation for general elections was not included in Sir Menzies' five tests.
The senior official who prompted the speculation told journalists after the speech that proportional representation was "not a deal maker or a deal breaker" in any negotiations to form a government, should no single party hold an overall majority.
He said Sir Menzies would take a more "flexible approach" to proportional representation than his predecessors.
Sir Menzies has refused to address a potential coalition government, insisting his only aim was to maximise the party's number of seats.
In his speech, he did stress the party's commitment to electoral reform, telling delegates the party's "ambition" was to have a "government elected by a system where every vote counts".
Sir Menzies, who received a four-minute standing ovation from delegates, coupled his call to Mr Brown with a scathing attack on Conservative leader David Cameron.
The Lib Dem leader, who has faced questions about his own age and whether, at 65 he is too old to lead his party, began by mocking recent revelations about Mr Cameron's past.
"Come on Dave, it's time to come clean. Admit your guilty secret.
"In your youth you were a Tory Boy and your heroes were Michael Howard, Norman Lamont and John Selwyn Gummer.
"With pin-ups like that, frankly, I'd want to keep my past private too."
Sir Menzies accused Mr Cameron of "ducking and weaving" and questioned his judgement on his decision to support the Iraq war.
"Teenage kicks are one thing, but you've got to grow up sometime," he said.