Sinn Féin has seen its support soar to its highest level in two years after putting down its controversial motion of no confidence in Minister for Health Simon Harris.

The latest Sunday Business Post/Red C poll shows that the party is up by five points to 18 per cent.

Taoiseach Leo Varadkar had accused the party of giving in to the "baying mob" by bringing forward the Dáil motion of no confidence in Harris over the cost overruns in the National Children’s Hospital project.

But even though the motion was defeated, it has helped Sinn Féin to its best Red C poll result in two years, in a boost for the party ahead of May’s local and European elections.

Fine Gael has seen its support drop by one point to 31 per cent, after a very damaging month of defending the near trebling of the budget for the National Children’s Hospital to €1.7 billion on its watch.

The poll findings are disappointing for the smaller parties who have been the main casualties of Sinn Féin’s rise in support

It is still ahead of Fianna Fáil, which is up by two points to 24 per cent. Fianna Fáil leader Micheál Martin is expected to mount a staunch defence of his decision to extend the confidence and supply agreement by one year in the ‘national interest’ at his party’s 79th ard fheis in the Citywest Hotel in Dublin tonight.

Independents are up by one point to 15 per cent but after a series of good polls, the Independent Alliance is down by three points to two per cent.

The poll findings are disappointing for the smaller parties, who have been the main casualties of Sinn Féin’s rise in support. Labour, which has had some good outings on the children’s hospital issue via Brendan Howlin and Alan Kelly, is down by one point to five per cent. The Green Party has been encouraged by new party branches springing up in towns around the country in response to the threat of climate change. But in this poll, it is down by one point to two per cent. The Social Democrats are unchanged on two per cent. Solidarity-People Before Profit are down by one point to one per cent.

Former Sinn Féin TD Peadar Tóibín has not seen any direct benefit for his new party Aontú, which is below 1 per cent when included in this poll for the first time. Renua is also below 1 per cent.

The telephone poll of 1,000 people was carried out by Red C between Thursday February 14 and Wednesday February 20. For in-depth analysis, plus an exclusive poll on the future of the confidence and supply agreement, read tomorrow's Sunday Business Post.