Martin is now less popular than Sinn Fein's McDonald
Micheal Martin's leadership of Fianna Fail is set to come under intense scrutiny this week after his personal popularity rating fell behind Sinn Fein leader Mary Lou McDonald.
Today's Sunday Independent/Kantar Millward Brown opinion poll shows Mr Martin's popularity lags behind a Sinn Fein leader for the first time in three years.
Since the last general election, satisfaction in Mr Martin's leadership of Fianna Fail has been at least 10 points ahead of Gerry Adams's stewardship of Sinn Fein.
However, Ms McDonald's personal satisfaction rating has increased seven points since she was appointed leader of Sinn Fein and is now polling at 46pc. Mr Martin's popularity dropped four points to 44pc in the same period.
Fianna Fail (27pc) remains five points ahead of Sinn Fein (22pc), although there has been a three-point swing toward Ms McDonald's party.
Sinn Fein is three points ahead of Fianna Fail in Dublin but trailing behind Mr Martin's party in Leinster, Munster and especially in Connacht/Ulster.
Mr Martin has faced serious division in his party over the forthcoming referendum on the Eighth Amendment of the Constitution and questions have been raised over his leadership.
Last week, 31 Fianna Fail TDs and senators posed for a photograph calling for a No vote in the referendum, which was in direct opposition to their leader's stance on abortion.
Yesterday he said he believed his party would support legislation allowing unrestricted abortion up to 12 weeks if the referendum passes.
Today's poll is sure to lead to further rumblings in Fianna Fail over Mr Martin's leadership, with a general election expected within the next year.
Meanwhile, Taoiseach Leo Varadkar's honeymoon period since being elected Fine Gael leader has come to an end as his popularity dipped for the first time.
Mr Varadkar remains the country's most popular leader, but his satisfaction rate (56pc) has dropped two points, while his dissatisfaction rate (34pc) has increased five points.
Support for his party has dropped two points but Fine Gael would still top the poll in a general election with 34pc of the vote. Satisfaction with the Government has dropped a point to 46pc, with dissatisfaction going up a point to 46pc.
Fianna Fail is still the least toxic political party, meaning it is more likely to pick up votes from supporters of other parties. Sinn Fein is the most toxic party, followed by Fine Gael which has seen its toxicity rate increase five points since the last survey.
The poll was taken between April 18 and 30, before the full extent of the cervical cancer scandal was apparent.
The state of the other parties is: Labour 5pc, Independent Alliance 5pc, Greens 3pc, Solidarity/People Before Profit 1pc, and non-aligned Independents 2pc.