The latest Irish Times/TG4 Ipsos B&A poll from Dublin Central suggests that the byelection in the capital is just as finely balanced as the one in Galway West. There are some similarities: a fragmented field in which transfers will likely prove decisive; a weakened Fianna Fáil struggling to remain competitive; and an electorate that appears increasingly detached from traditional party loyalties.

But there are differences too. Whereas in Galway West it is a Government candidate, Fine Gael’s Seán Kyne, who holds a narrow advantage, in Dublin Central Janice Boylan of Sinn Féin is marginally ahead.

That is hardly a surprise. Party leader Mary Lou McDonald topped the poll in the general election and the constituency has been a Sinn Féin stronghold for some time.

Yet Boylan will be looking over her shoulder at the Social Democrats’ Daniel Ennis, who trails her by only a few points. The poll also shows the Social Democrats performing strongly in second preferences. With transfers from Green, Labour and People Before Profit voters available, and probably some support from Government party voters anxious to keep Sinn Féin out, Ennis looks well placed at this stage.

The poll points to an increasingly competitive relationship between Sinn Féin and the Social Democrats for progressive urban voters. Sinn Féin remains the largest force on the left, but no longer dominates the Opposition as it once did. The Social Democrats continue to consolidate support among younger and more liberal urban voters, while also benefiting from strong transfer friendliness.