Updated 16.05

SINN FÉIN senator Pearse Doherty has roared into a substantial lead in the opinion polls ahead of next week’s Dáil by-election for the vacant seat in Donegal South-West, it has emerged.

An opinion poll commissioned by Red C on behalf of Paddy Power bookmakers shows the Sinn Féin candidate, who essentially forced the government into holding the by-election after the High Court ruled that it had caused an “unreasonable delay” in blocking it, commanding 40% of the potential first preference votes.

By comparison, his closest challenger – Senator Brian Ó Domhnaill, of Fianna Fáil – carries 19% of the potential first preference vote, while Fine Gael councillor Barry O’Neill is a further three points back, on 16%.

Labour’s candidate, Cllr Frank McBrearty Jr, commands 15% of the first preference vote, while independents Cllr Thomas Pringle (himself a onetime member of Sinn Féin) and Ann Sweeney command 8% and 2% support respectively.

Doherty’s enormous support is almost certain to guarantee him election to the seat; the poll also finds that the Sinn Féin candidate commands 19% of the second-preference support of the electorate, easily pushing him over the 50% +1 threshold needed to secure by-election victory.

Labour’s McBrearty commands the largest section of second-preference support, with 20% of voters saying they would give him their Number 2 preference, ahead of O’Neill with 14% and Ó Domhnaill with 10%.

The Dáil seat has been vacant for 17 months, since the election of incumbent Fianna Fáil TD Pat ‘the Cope’ Gallagher to the European Parliament in June 2009.

Worse news for Fianna Fáil

The poll – which sampled 510 adults by election between last Saturday and Tuesday – provides even worse news for Fianna Fáil elsewhere. The same poll asked candidates to indicate their preference if a General Election was to be held, and shows Fianna Fáil’s likely candidates lagging well behind the opposition in popularity.

Doherty polls 31% of first-preference support if a full general election was to be held – enough to guarantee election on the first count in the three-seat constituency – while McBrearty comes second, with 18% of voters saying he would be their first choice.

Fine Gael incument Dinny McGinley (with 13%) and stablemate O’Neill (with 12%) both command greater shares of support than Tánaiste Mary Coughlan, who commands the first-preference support of just 10% of likely voters.

Brian Ó Domhnaill, assuming he would be the second Fianna Fáil candidate, carries the support of just 9% of voters – meaning that even if the entirety of one Fianna Fáil candidate’s second preferences were transferred to the other, the party would still struggle to win one of the three seats.

The poll also suggested that 46% of Donegal South-West voters believe Labour’s Eamon Gilmore would make the best prospective Taoiseach after the next general election, well ahead of both Fine Gael’s Enda Kenny on 18% and Brian Cowen on 13%.