A Bill that prevents people convicted of serious criminal or paramilitary offences from holding special advisory posts for Northern Executive Ministers was last night adopted by the Stormont Assembly.
Its proposer, the Traditional Unionist Voice leader Jim Allister, said it was designed to "right a great wrong".
Mr Allister said the legislation should be called "Ann's Law", in respect of Ann Travers, sister of Mary Travers who was murdered by the IRA while leaving Mass with her father Tom, a Belfast judge and mother Joan in south Belfast in 1984.
It was a campaign launched by Ann Travers opposing the appointment of Sinn Féin special adviser Mary McArdle, who was involved in her sister’s killing, that led to Mr Allister putting down his motion.
Ms Travers attended yesterday’s debate in the company of Catherine McCartney, whose brother Robert was killed by alleged IRA members outside a Belfast city centre pub in 2005.
Some initial attempted filibustering by Sinn Féin delayed a vote on the Bill by over two hours but at 8.24 pm last night it was carried by 56 votes to 28.
In the past two weeks the SDLP had indicated it would support Sinn Féin’s petition of concern. Sinn Féin argued the legislation was contrary to the spirit and letter of the Belfast Agreement, a view with which a number of SDLP members sympathised.
But following an escalation of the campaign by Ann Travers and interventions supporting her by former SDLP ministers Seamus Mallon and Bríd Rodgers, the party altered its position. It last night abstained in the vote having earlier argued that it was “flawed”.
Sinn Féin had submitted a petition of concern to try to obstruct the legislation. It has 29 members, which was one short of the 30 required to succeed with such a parliamentary blocking device.
Under the legislation anyone convicted of criminal or paramilitary offences carrying sentences of five years or more is not allowed to hold the post of special adviser to Ministers in the Northern Executive.
It also applies to current special adviser Paul Kavanagh, who works for the Sinn Féin Deputy First Minister Martin McGuinness.
Mr Kavanagh, who was convicted of killing three people during an IRA bombing campaign in England in 1981, is from Derry and married to the Sinn Féin MEP Martina Anderson, herself a former IRA prisoner.
That Derry connection resulted in the three SDLP Derry MLAs – Colm Eastwood, Pat Ramsey and Mark H Durkan – coming under pressure from Sinn Féin to break party ranks and for one or more of the three to support the blocking petition of concern.
The debate was due to conclude at 6pm yesterday but a lengthy contribution by the first Sinn Féin speaker, North Antrim MLA Dáithí McKay, who spoke for just short of two hours, and contributions by several other MLAs, resulted in the debate running to shortly before 8.15pm when the vote was taken.