OTTAWA — A brewing grassroots revolt prompted an abrupt about-face from Liberal Leader Michael Ignatieff on Quebec's proposal to impose health-care user fees.

After first declaring Quebec's plan legal, Ignatieff has reaffirmed the long-standing Liberal position that user fees are a violation of the Canada Health Act.

The flip-flop follows mounting opposition to the proposal in Quebec and within his own party ranks.

"I want to make it very clear that our party, and I personally, am a passionate defender of the Canada Health Act," Ignatieff told reporters following a caucus meeting Wednesday.

"If the government of any province were to introduce user fees, it is our belief that that would be in contravention to the Canada Health Act and we would oppose it."

The act - something of a sacred cow for Liberals since it was introduced by the Trudeau government in 1984 - explicitly prohibits user fees and empowers the federal government to financially penalize provinces that impose them.

Ignatieff's comments were in stark contrast to the initial thumbs up the Liberal leader appeared to give Quebec's plan to charge $25 for each visit to a doctor's office.

Shortly after the proposal was floated in Quebec's March 30 budget, Ignatieff said: "In our opinion, what counts is maintaining universality of access to the system. We believe, and it's a question of details, that Quebec's propositions conform to the Canada Health Act."

His response privately stunned Liberal MPs, who were not consulted, and infuriated many rank and file Liberals, particularly in the party's youth wing.

It rankled all the more that only days earlier, at a vaunted thinker's conference in Montreal, Ignatieff had billed himself as a new-style, collaborative leader who consults widely with a vast network.

Samuel Lavoie, president of the Young Liberals, fired off a letter to party president Alf Apps, expressing his "shock" and "disappointment" over the leader's embrace of the "obscene" user fee proposal.

In the letter, obtained by The Canadian Press, Lavoie said the proposed fee amounts to an "utterly immoral" tax on disease. He said it would unfairly penalize the poor and chronically ill and potentially risk the lives of those who put off seeing a doctor to avoid paying the fee.

Moreover, Lavoie noted that support for Premier Jean Charest's government has nose-dived since the budget was unveiled. He questioned why the federal Liberal party would want to embrace "the most unpopular measure of a very unpopular budget," potentially alienating progressive voters it needs to win back from the NDP and Green party.

In a subsequent speech near Montreal, Ignatieff was somewhat more equivocal about the Charest budget. He said provinces need "room to experiment" with ways to cut health-care costs but said that should be within "the framework" of the Canada Health Act.

He called guaranteed universal access "the spine of Canadian citizenship" but did not mention user fees, much less specifically rule them out.

Dissatisfied, Lavoie spearheaded a motion, approved unanimously Tuesday by the Young Liberals' national executive, urging the party to "vigorously oppose health care user fees and any other actions which violate the law, purpose and spirit of the Canada Health Act."

The same motion was adopted Tuesday night by the executive of the British Columbia wing of the party and various other party groups were considering following suit.

Liberal MPs were buzzing approvingly about it at their caucus meeting Wednesday.

When he emerged, Ignatieff offered a clarification of his position on user fees, without being asked by reporters. He suggested his initial response to the Quebec budget had been misunderstood and had all been in the context of Charest's intention to abide by the Canada Health Act.

"Mr. Charest, to repeat, has said he wants to find solutions to the financial problems of the Quebec health system within the framework of the Canada Health Act," Ignatieff said.

"I'm saying great, let's work together that way. But understand what that means to us as leaders of a federal party that is proud to have brought in the Canada Health Act and stood with it for a generation. It means no user fees."

In an interview, Lavoie said he's concerned the Charest government hopes to avoid a breach of the act through a technicality - collecting the user fee at tax time, rather than at doctors' offices. Hence, he said federal Liberals must protect both the letter and spirit of the act.

Lavoie said he was "very satisfied" with Ignatieff's clarification.

"We couldn't be happier."