Michelle Williamson said she was taking the legal action on behalf of thousands of innocent victims of terrorism, claiming the new victims' panel is unacceptable.

She is being backed by 15 victims' group, all of whom say they will not work with the new commission.

Ms Williamson, whose parents George and Gillian died in the 1993 IRA blast at Frizzell's fish and chip shop on the Shankill Road, said she found the new panel unacceptable because of the presence of Patricia MacBride, whose IRA brother was shot dead by the SAS.

There was an uproar among unionists and victims' groups when the new commission released a statement referring to Ms MacBride's brother as an "IRA volunteer" who was "killed on active service".

The other three members are RUC widow Bertha McDougal, former TV presenter Mike Nesbitt and Brendan McAllister, the director of Mediation Northern Ireland.

They were appointed after a lengthy process that originally called for a single victims' commissioner.

Speaking outside the High Court after lodging the papers for her legal challenge, Ms Williamson said: "I am all for a commission, yes, but one not four. Is it a case of eeny, meeny, miny and mo?

"One is what we were promised and one is what we should get – someone who is completely neutral."

Willie Frazer from victims' group Families Acting for Innocent Relatives, who is supporting the legal move, says he expects movement on the case in around a week.

He says he is convinced the action will succeed and he also hit out at the amount of money set aside to aid victims and what he claims is an attempt by the authorities to "blackmail" victims' groups into accepting the new commission.

"We can't deal with this commission.

"This is a political appointment – out of the four it's quite obvious that one is for the republicans and one supposedly for the innocent victims.

"This is not about the actual appointments – they have made political appointments here.

"It's not about the right people for the job, it's about making people acceptable to the republican community and the unionist community and unfortunately that hasn't worked either way, so this commission is a complete and utter failure.

"If a large section of the victims are not prepared to deal with the commission given the language that has been used what good is the commission being there in the first place?"

He denied the legal move would hold up help for victims as out of the £33 million claimed to have been allocated to victims, only £1.8 million was actually reaching victims' groups.

"This will not delay the help that is already out there for the victims – we will continue to do the work that we have been doing," he added.

"They have frozen the money for another year – there is no more help for the victims' sector for this financial year so they can't use the excuse that this is delaying help for the victims."