SINN Féin leader Gerry Adams has said Stormont has reached a "defining point" in the wake of First Minister Arlene Foster's refusal to stand aside while the Renewable Heat Incentive is investigated.

Writing in his weekly Andersonstown News column, Mr Adams said his party cannot “continue to countenance the manner in which the DUP conduct business within the Executive and the Assembly.”

Yesterday Ms Foster said again that she would not stand down and claimed calls for her to do so were misogynistic.

The Sinn Féin president re-iterated Sinn Féin's call forMs Foster to step aside, saying: “Can this be sorted out? Of course it can. That would require Arlene Foster to do what Peter Robinson did. She should step aside to facilitate an independent process which gets to the facts of the RHI scandal effectively and quickly. This is a straight forward case. The First Minister has been in office for a relatively short time. If she wants to continue in that office she needs to do the right thing.”

Mr Adams also attacked the DUP's record in government, saying: "For almost ten years Martin McGuinness and our Assembly team have navigated a way through a number of crises and scandals. A lot of good work has been done by the Executive and the Assembly and significant progress has been made on many issues, including on cross border and all-Ireland matters.

“On other issues there has been little or no progress. I’m thinking here of the long standing absence of a Bill of Rights. There has also been a shameful lack of respect accorded to the Irish language and to those citizens who wish to live their lives through Gaeilge.

“The reprehensible decision on the eve of Christmas to cut funding for the Líofa programme is just one example of this.”

He continued: “Among other examples of DUP messing have been the decision to renege on the Programme for Government commitment on the Long Kesh site; the DUP’s resistance to the legacy and truth recovery mechanisms of the Stormont House agreement; and the Project Eagle debacle.

“These issues, and the previous Christmas time crises, mean that even before the emergence of the Renewable Heat Incentive (RHI) scandal the behaviour of the DUP had already led to a considerable lack of public confidence in the institutions. The RHI scandal and the manner in which the DUP has handled it, has significantly deepened a crisis that already existed.

Mr Adams repeated the call for a judicial investigation into the RHI scandal: “When the Assembly resumes a Sinn Féin motion on the RHI scheme will be debated. It is a common sense proposal which comprehensively addresses the many issues which have given rise to public concern. It calls on the First Minister to stand aside in order to facilitate an independent, time-framed, robust and transparent investigation and until a preliminary report is presented. It will also propose that this investigation would be undertaken by an independent judicial figure from outside this jurisdiction and with the power to compel witnesses and documents.”

He added: “Over the Christmas break Sinn Féin took legal advice on the potential efficacy of our proposals. That advice, and we have accepted it, pointed to the need to address in clear terms the issue of compelling persons and papers in any investigation to make it effective.

“But whatever the outcome of that debate the reality is that the political institutions have reached a defining point. Neither the public nor Sinn Féin can continue to countenance the manner in which the DUP conduct business within the Executive and the Assembly.”