ROBIN Newton was urged yesterday to reflect "as to whether he is the man to lead the Assembly in 2017".

The Speaker faced unprecedented criticism from fellow MLAs for refusing to specify under which assembly rules yesterday's special sitting was being held.

The DUP MLA, who has also been criticised in recent weeks over his handling of questions relating to the Charter NI funding controversy, recalled the assembly after a request for First Minister Arlene Foster to make a statement about the Renewable Heat Incentive (RHI).

However, because Deputy First Minister Martin McGuinness withdrew support for the DUP leader's statement at the weekend, MLAs insisted it no longer carried the necessary mutual consent which characterises the joint office.

All parties except the DUP initially walked out when Mr Newton refused to hear points of order when opening proceedings, but later, following an adjournment, a succession of MLAs challenged the speaker on the authority he was acting on.

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He said: "Let me be quite clear – I have taken legal and procedural advice from the officers of the assembly and I am content that we are proceeding with their advice in line with standing orders," Mr Newton said.

Ulster Unionist leader Mike Nesbitt said afterwards that Mr Newton had overseen a "farce".

The Strangford MLA said Mr McGuiness had made it clear that Mrs Foster would not be speaking with his authority – thus invalidating standing order 11, which provided the basis for the DUP leader's statement.

"When I challenged the speaker repeatedly he was unable to name a standing order, eventually pointing the house to standing order 18," Mr Nesbitt said.

"But this refers to ministerial statements and the whole point is that this is a personal and not ministerial statement by Mrs Foster."

The Ulster Unionist leader urged the speaker to "reflect over Christmas as to whether he is the man to lead the Assembly".

Former deputy speaker John Dallat was also critical of Mr Newton.

"Willie Hay (former speaker) protected the post well and no-one could have found fault with him but the current speaker has failed to rise above the shambles," he said.

The former SDLP MLA claimed Mr Newton's authority was already undermined after he had to apologise for not declaring links to Charter NI when ruling against an urgent debate on its funding and yesterday was "not in control".

Mr Newton later sent a letter to all MLAs saying he acknowledged their "genuine frustrations and concerns".

He said that because the recall of the assembly had been exercised jointly by the first and deputy first ministers, any revocation must also be undertaken jointly.

He also said it was not for him to review how ministers have followed executive procedures.

"Assembly procedures may never deal effectively with unusual circumstances and in that context it may fall to me to make difficult judgements on the basis of procedural advice.

"Clearly it would have been better if the assembly had not been placed in this position by the Executive Office today and I will be raising this further with ministers."