The walk-out by Ireland East European MP Nessa Childers adds to the pressure following Labour’s humiliating fifth place in the Meath East by-election.
Ms Childers urged colleagues to follow her example and rebel, as she believes the party has taken the wrong direction in Government.
“I entered politics to help people, and am now resigning from the parliamentary Labour Party because I no longer want to support a Government that is actually hurting people,” she said.
“My dissatisfaction with the party in Government has been known for some time; however, recent statements from the Labour ministers have dismayed me. They continue to insist that because of the dire economic situation there is no alternative to current Government policies.”
As the leadership risked a grassroots backlash by trying to push the party’s annual conference beyond the October budget in a bid to silence critics, Ms Childers accused Mr Gilmore of “attacking” those who were trying to defend traditional Labour values.
“The party leadership’s strategy of attacking people who are loyal to the party’s stated policies; coupled with their objection to a special party conference and objection to renegotiating the programme for Government, signals that they are completely cut off from the concerns of the party members and Labour Party ideals and values,” she said.
Ms Childers, who remains a Labour Party member, did not call for Mr Gilmore to be replaced, but said Cabinet members need to radically change their agenda to restore credibility.
Labour is expected to lose all three of its MEPs at the Euro elections next summer. After seeing its share of the vote in Meath East fall from 21% two years ago to just 4.6%, Labour’s call for a review of the Programme for Government was rejected by Taoiseach Enda Kenny.
Rebel party chairman Colm Keaveney demanded a “showdown” party conference as soon as possible in order to avoid a “meltdown” in Labour, but Mr Gilmore appears determined to delay such a gathering until after the budget.
Gilmore loyalist and Labour TD for Dublin South East Kevin Humphreys insisted that the MEP’s action would have no impact.
“Nessa is going to have little or no influence on that budget because she stepped off the pitch,” he told RTÉ.
A spokesperson for Labour tried to downplay the move by describing Ms Childers as being “semi-detached” from the party for some time, adding: “It seems some people are more comfortable with the Labour Party in opposition.”