Former Lib Dem leader Charles Kennedy has addressed his party's conference, calling for an "all out assault on poverty" at the next general election.
Mr Kennedy was given a warm welcome by delegates
Delegates in Brighton cheered as Mr Kennedy urged them to confront the "cynics" who said taxing the rich was "electoral suicide".
Members have backed the leadership's plans to cut taxes for low-income families, paid for by new green taxes.
Mr Kennedy said the party must never give up the fight for social justice.
The former party leader, who was forced to resign 18 months ago after admitting receiving treatment for a drink problem, told delegates not to be defensive about their policies and to "go on the attack".
And he blasted the "usual suspects and the usual sources" who were attacking the party, arguing that when he introduced a policy of increasing the top rate of tax, it had returned the "highest number of MPs for 80 years".
Delegates were told that you could tell "a lot" about a party over its attitude to foreign affairs, but the real "litmus test" was its priorities at home.
He said: "If there is one litmus test that we are going to face again, with a view to the next general election it is going to be an all-out assault on poverty and growing social inequalities in our country and the promotion of greater social justice.
"I want to challenge head on the criticisms that we are already seeing in the course of the conference coverage this week here being levelled at us from all the usual suspects and all the usual sources.
"We have been here before."
He went on: "I was, a few years ago, a member of that much smaller parliamentary party, which on the eve of that general election, committed us all to a penny on income tax devoted to education.
"The sceptics said: 'You are committing electoral suicide'. It was one of our most salient telling policies.
"At the last election we held our heads up high and we faced the top income earners in this country and said that if you believe in fairness you should believe in a more progressive top rate of taxation.
"We returned our highest number of MPs for 80 years."
Mr Kennedy has refused to rule out a return to frontline politics at some stage, but he said there was no desire for a challenge to party leader Sir Menzies Campbell.
"There is no appetite in this conference or beyond to indulge ourselves in any leadership machinations," Mr Kennedy told BBC News 24.