UUP leader Reg Empey has said he regrets his role in the loyalist Vanguard movement. In a television debate he also said that mainstream unionism used loyalist paramilitaries through the 1970s and eighties and now was the time for unionists to redress it.
Speaking on BBC Northern Ireland's Let's Talk earlier this week Sir Reg said he had been involved with the Vanguard as a young man in the 1970s to oppose the Sunningdale power-sharing agreement.
The Vanguard has been described as a political pressure group within unionism designed to involve loyalists in politics.
Sir Reg said unionist politicians sat around a table with loyalist paramilitaries during the 1974 Ulster Workers Council strike.
He faced criticism on the programme for having invited PUP leader David Ervine, whose party is aligned to the Ulster Volunteer Force (UVF), to join the party at Stormont when the assembly reconvened last week.
Sinn Féin's Conor Murphy, SDLP leader Mark Durkan and the DUP's Gregory Campbell all condemned the move which Sir Reg has said will strengthen unionism and take a ministerial position from Sinn Féin.
Critics have said the UUP leader approached two other assembly members before Mr Ervine.
Sir Reg has refused to reveal who he contacted about an assembly deal.
The new addition to the assembly group makes the UUP the second largest party after the DUP.
Commentator Brian Feeney said the links between mainstream unionism and loyalist paramilitaries are well documented and that it had been the Ulster Unionists who had "brought the gun into Irish politics in 1913" during the gun running at Larne, Kilkeel and Portavogie.
The Ulster Resistance was formed in November 1986 by then DUP leader Ian Paisley and his now deputy leader Peter Robinson was also a member.
Organised into nine 'battalions' its members wore a red beret.
Mr Feeney said it had imported weapons from South Africa with the help of British intelligence and divided some of them between the UDA and UVF.
"Peter Robinson led an incursion into the Republic at Clontibret in 1986. Two gardai were injured and he was fined 15,000 Irish pounds. He was held for a night in jail in Limerick and this has been glossed over," he added.
The Third Force, meanwhile, was set up by Mr Paisley and its members took to holding demonstrations where they waved firearms certificates.
"It was a Grand Old Duke of York organisation – they marched up and down and around the square in loyalist towns like Newtownards wearing balaclavas," Mr Feeney said.
"It was a show of strength – a threat to the British government – 'you try and bring in any reform and this is the resistance you will face'," he added.
The Ulster Workers' Council (UWC) strike brought down the Sunningdale power-sharing agreement in 1974 and Mr Feeney said the UUP and DUP had sat on the council with the UDA and UVF.
In 1996 South Antrim DUP MP Willie McCrea shared a platform at a Portadown rally with LVF leader Billy Wright, who was shot dead by the INLA three years later in the Maze Prison.
Asked about this on the television programme DUP East Londonderry MP Gregory Campbell said Mr McCrea had joined the loyalist on the stage because Wright had received a death threat and the politician condemned all violence.
