Foster fends off RHI attacks during first TV debate of campaign

However, there was a striking lack of any attacks between the UUP and SDLP leaders, who gave some public indication of their developing political relationship as they attempt to persuade the public that they can form a credible alternative to the DUP-Sinn Fein Executive.

Mr Nesbitt said the UUP and SDLP would be “willing partners” in any future administration and said that the election should be a “referendum” on RHI and how the big two parties had handled government here for almost a decade.

Both Mrs Foster and Sinn Fein’s Michelle O’Neill sought to remind UTV viewers of Mr Nesbitt’s weekend comment about transferring his second preference vote to the SDLP.

Mrs Foster claimed that transfering to nationalists meant that “you could bring about a border poll and that’s very, very dangerous”, something which Alliance leader Naomi Long said was simply not in line with the law as set out in the 1998 Agreement.

However, Mrs Long also had a jibe at the UUP over its political relationships – with the Conservatives, the DUP and now the SDLP – over recent years, saying that the party was “the Lothario of Northern Ireland” because it had “hopped in and out of bed with nearly every other political party”.

Setting out a robust stance from the off, SDLP leader Colum Eastwood used his opening speech to say that “one person on this panel designed the scheme that is costing us all half a billion pounds; another person on this panel let them away with it”.

And, rejecting Mrs Foster’s argument that the election was about wider discontent within Sinn Fein, Mr Eastwood said: “We got here because of the arrogance of Arlene Foster”, adding: “People in my community had a lot of hope for Arlene Foster and she’s let us all down.”

Mrs Foster clashed several times with Ms O’Neill, particularly over whether she should have stood aside as first minister. The DUP leader reminded Ms O’Neill that the High Court had found that she had broken the ministerial code and it had also been found that her party colleague Conor Murphy had discriminated against a Protestant for a major public appointment, but on neither occasion had they stood aside.

The issue of an Irish language act barely featured last night, but Ms O’Neill spoke a few token words of Irish at the outset, saying “we are moving forward”.

And, speaking about the RHI scheme, Ms O’Neill alleged – though did not substantiate what she claimed – that the DUP “withheld information deliberately from their partners in government”.

At the end of the debate, Mrs Foster was asked about the DUP’s huge advertising spend across the rest of the UK during the Brexit campaign, something in which national media have begun to take an interest.

Mrs Foster said that the DUP had received dontations “from an organisation in England who wants to see the Union kept” to fund the ads.