Lucinda Creighton forfeited both her ministerial office and parliamentary party membership when she defied Fine Gael on abortion legislation in July 2013.

The former minister of state for European affairs, who represents Dublin South East, objected to the inclusion of a suicide clause in the Protection of Life During Pregnancy Bill.

She had appealed for a relaxation of the “archaic and out-of-date” whip system but this was firmly ruled out by Taoiseach Enda Kenny, with whom she had repeatedly clashed.

Her position on abortion, which has changed since her student days, was influenced by speaking to friends who had a “negative” experience of termination, she told The Irish Times in the aftermath of her departure.

She became the leading light of the Reform Alliance, a group of former Fine Gael parliamentarians expelled from the parliamentary party for voting against the whip.

One prominent member, Denis Naughten, who left Fine Gael over a local hospital issue in his constituency, has already ruled out joining a new party.

However, Senators Fidelma Healy-Eames and Paul Bradford, Ms Creighton's husband, are expected to come on board the new party being announced today.

Other potential candidates include other Reform Alliance members Terence Flanagan and Billy Timmins, although he renewed his membership of Fine Gael last April.

Ms Creighton, who is 34 and a qualified barrister from Claremorris, Co Mayo, became the youngest member of Dublin City Council in 2004.

First elected to the Dáil in 2007, she took the seat of the then Progressive Democrats leader and former minister for justice Michael McDowell.

She opposed Mr Kenny’s leadership of Fine Gael in 2010, when she was a key player in the unsuccessful heave. However, Mr Kenny appointed her a junior minister the following year.

Widely perceived as having thrived in the European portfolio, she took a lead role in the Government campaign on the fiscal treaty referendum and was a key figure in Ireland’s EU presidency.