The campaign exposed other major policy disputes between the parties.

Sinn Fein's northern leader Michelle O'Neill said: "I think it's a brilliant day for equality, I think it's a great day for democracy.

"The vote has increased. I think that is because people knew that action needed to be taken, they have had their say, we now need to get down to the business of fixing what's wrong and delivering for all citizens."

After being elected in her Fermanagh and South Tyrone constituency, Mrs Foster said: "I think it's very clear that was absolutely not about RHI. It may have been the excuse but it certainly wasn't the cause of the election.

"The cause of the election was Sinn Fein and republicanism wanting to rerun the election, they have mobilised their vote in a very effective way.

"I am pleased that the DUP has come out as the largest party in terms of votes. It is very clear in terms of unionism that it is the Democratic Unionist Party that speaks for unionism."