The Alliance Party has boycotted a Westminster committee over its decision to invite a controversial loyalist blogger to give evidence.

Alliance leader Naomi Long said the Northern Ireland Affairs Committee had undermined its credibility by asking Jamie Bryson, an outspoken critic of the 1998 Good Friday Agreement, to give evidence to its inquiry into the region’s democratic deficit.

He came to prominence after playing an active role in Northern Ireland’s Union flag protests of 2012/13.

Mrs Long had also been due to give evidence in person at Westminster but has now rebuffed the invite.

The party said it would let its written evidence to the committee stand.

The former MP said the process had descended into “farce and ridicule”.

She questioned why groups such as Friends of the Earth had not been invited to give oral evidence.

“We never said we wouldn’t talk or listen to Jamie,” she tweeted.

“There must be a threshold of credibility for evidence to a Parliamentary Ctte.

“The circus he creates has already obscured the purpose of the inquiry. We don’t want to be part of that. Our written evidence will stand.”

Mr Bryson, who is giving evidence next week on behalf of the group Unionist Voice Policy Studies, criticised Alliance’s stance.

“The Alliance Party’s withdrawal demonstrates a severe lack of tolerance for others viewpoints,” he said.

“The contrived controversy around me representing the group is a fig leaf.

“The real issue here is an intolerance of different viewpoints and the fury that grassroots loyalism would dare to engage in an open inquiry.”

Chairman of the committee, Conservative MP Dr Andrew Murrison, said he did not agree with Mr Bryson’s views but it was right he should have the opportunity to voice them.

“He is a controversial figure and views are divided on him,” he told BBC Radio Ulster.

“He is a voice, he represents a small but significant voice in Northern Ireland – on that basis the committee decided it was reasonable on balance to invite him to attend.”

Ulster Unionist Party MLA Doug Beattie said Alliance had made the wrong decision.

“Alliance style themselves as a progressive and open political party but on occasion they do give the impression that they have a higher virtue than everyone else and that their opinion would be in some way corrupted by listening to opposing opinions,” he said.

“Their decision to withdraw from appearing in front of the Northern Ireland Affairs Committee due to the fact that Jamie Bryson is attending is disappointing and I just cannot understand their rationale.

“Jamie Bryson does not represent my view of Unionism and I would disagree with much of what he says.  But he has an opinion, he made a submission that was accepted, and therefore his opinion should be heard.”

SDLP leader Colum Eastwood said he would still give evidence to the inquiry.

A party spokesman branded Mr Bryson an “eejit” but added: “We believe it is better to robustly take on and take apart his arguments than to allow him free reign and an open microphone.”