Image caption Sammy Wilson was reported to the Stormont standards commissioner after he called TUV leader Jim Allister a "thug" during a commitee hearing

A DUP special adviser who played a central role in a Stormont inquiry was a "weak and vulnerable" witness, according to a senior party colleague on the committee hearing evidence.

Sammy Wilson made the claim during an interview with the Stormont standards commissioner, Douglas Bain.

Mr Wilson was reported to Mr Bain after accusing the TUV leader Jim Allister of "bullying" adviser Stephen Brimstone.

He called Mr Allister a "thug" during a Social Development Committee meeting.

In a transcript of the interview seen by the BBC, Mr Bain asked Mr Wilson what he meant by using the word "bully".

Mr Wilson said: "I mean someone who harass [sic] - first of all, who gets people into a position where they're vulnerable and then harasses them.

Mr Bain replied: "OK. Was in your view, was Mr Brimstone a weak or vulnerable witness?"

Mr Wilson said: "He was, certainly, and he was being harassed and he was not being given any protection by the chairman [Alex Maskey] during that harassment either, and, of course, his treatment, his treatment varied greatly with the treatment that was given to a number of other witnesses who, when the chairman thought they were being pushed too hard, would have intervened.

"He didn't intervene on this occasion, cause he was quite happy for somebody else who was more competent bullying to do the bullying for him."

Mr Bain then asked: "Mr Brimstone is a senior civil servant, isn't he?"

Mr Wilson said he was.

"And yet you think he's weak or vulnerable," Mr Bain said.

'Fear and trepidation'

Mr Wilson said "Well I think that anyone who's been placed in that position tends to - some of them come in with more fear and trepidation than others. I have seen witnesses, fairly strong witnesses, having to go towards committees and being made a nervous wreck."

Mr Bain said: "And earlier during the meeting on 16 October, he had in fact sought the assistance of the chair in declining to answer a question, hadn't he?"

Mr Wilson replied: "As he's entitled to."

Mr Bain said that "the chair had supported him on that occasion, hadn't he?"

Image caption Mr Wilson said Stephen Brimstone was a vulnerable witness who was bullied during the hearing

"The chair may have done, yes. I'm sure your recollection's very good," Mr Wilson replied.

Mr Wilson, who was subsequently found to have broken the MLAs' code of conduct, accused Mr Maskey of allowing Mr Allister "to do his courtroom act" on other witnesses.

But he claimed Mr Maskey had "changed his attitude totally" following the "thug" incident.

"So I think it probably, it got the message over to both of them that they are not there as some type of Gestapo-type officers, but they do have a responsibility to treat witnesses in a proper way," he added.

Mr Wilson denied discussing with anyone else before the meeting how to "protect" Mr Brimstone from questioning.

Mr Bain said it had been suggested that his intervention at the meeting was not on the spur of the moment but "contrived".

However, Mr Wilson replied: "If you think that I sit down and contrive these things, Mr Bain, just think again."

'Pointing his finger at me'

At one point during the often heated interview, that lasted 51 minutes, Mr Bain said: "Just for the record, Mr Wilson is leaning forward and pointing his finger at me."

In another answer Mr Wilson claimed that MPs at Prime Minister's Question Time in Westminster sometimes behave worse "than people at a Linfield and Cliftonville football match".

He said this while denying his behaviour during the committee hearing had brought the assembly into disrepute.

Mr Wilson also claimed no members of the committee were "impartial."

"Let's make this clear. Everyone who is on that committee has approached this subject from a predetermined point," he said.

"They have their mind made up. I am not impartial. The chair's not impartial. The rest of the committee members aren't impartial.

"And I think if you, since you've had a chance to read through some of the Hansards, you'll see quite clearly that some of us go after some witnesses a bit harder than we go after other witnesses because that reflects the partiality which is there."

As for the disciplinary process, he says it won't deter him from making similar remarks in future saying "Should the same situation happen again I'd have no hesitation, should you be bringing me in here every week for a conversation like this, in doing the same."