Fianna Fail had seen nothing like it for years — John McGuinness, a backbench TD — risked the wrath of an uncomfortable leadership to deliver an uncompromising message to his party colleagues.

The deputy for Carlow-Kilkenny told them he intended to continue his public criticisms of the government when he felt them justified. If that meant speaking out in the media, so be it. “I am comfortable with that,” McGuinness said.

By the end of last Wednesday’s long parliamentary party meeting, Bertie Ahern was left in no doubt about the internal problems he faces. As the party braces itself for the toughest cuts in spending in more than a decade one of the problems is the taoiseach’s continuing inability to quell the unrest among his backbenchers.

The leadership increasingly regards McGuinness as one of the primary culprits for stoking the discontent. But this self-made businessman was not alone in his criticisms. More than 30 TDs and senators rained down on the party leadership, claiming Fianna Fail was being dragged away from its core values. For more than two hours, the taoiseach and his ministers sat through a sustained assault on the direction in Fianna Fail policy.

Superficially, the issue was the first-time buyers’ grant, which according to the budget estimates is to be abolished. But the common thread running through almost all the contributions was that its abolition represented something deeper — it symbolised a steady shift in Fianna Fail away from the ordinary workers in favour of the rich and the super-rich.

What really stung the leadership was the diversity of people who spoke out. It was not simply “the usual suspects”. TDs like John Maloney of Laois-Offaly, who warned his vote could not be taken for granted, or Marie Hoctor, the newly elected deputy for Tipperary North who openly questioned the emerging values of the party, could hardly be seen as troublemakers.

Aside from those who spoke, Ahern knows there are at least another 10 members with similar views who stayed silent. It means almost half the parliamentary party is seriously questioning where it is going.

While the meeting did not degenerate into personalised attacks, it still amounted to the most controlled display of anger with the leadership for many years.

There is no doubt that McGuinness has been one of the most vocal critics of the government since the summer. Only last weekend he warned ministers not to attempt to plunder scarce public resources to shore up their own local popularity when the going gets tougher over the next few months.

While he is far from being universally popular among his colleagues, his remarks struck a chord with many of them. The problem for Fianna Fail is that they cannot get a handle on whether McGuinness is merely reflecting deep discontent or actively promoting it.

His readiness to speak out has helped create an atmosphere where others feel they are not obliged to hold their tongues or simply act as political cheerleaders.

With a successful transport business behind him and a solid base in local authority politics, McGuinness is ambitious. Having been first elected to the Dail in 1997 he was one of that class who would have aspired to a promotion to the junior ministerial ranks after the May general election.

Like others in the party, he was astounded when Ahern reverted to minimalist ministerial changes, having previously promised a major shake-up.