Relatives of people murdered by loyalists in the North amid claims of security force collusion are picketing British military intelligence headquarters in London today.
Firinne, the victims group campaigning for the truth about collusion between British state agents and loyalists is expecting up to 100 campaigners to protest at Conservative Party offices as well as at the MI5 headquarters.
The demonstration is being held to coincide with the start of new political talks in Belfast to break the deadlocked peace process.
Group spokesman Mr Mark Sykes said: "The families are determined that the truth surrounding the murder of our loved ones will not continue to be suppressed by the culture of concealment which operates at the heart of the British government."
Organisers travelled to London after staging a picket at Stormont, where all sides have gathered to begin a major review of the 1998 Belfast Agreement.
Mr Sykes, who was wounded in a 1992 Ulster Freedom Fighters gun attack on a south Belfast betting shop which left five Catholics dead, warned the British authorities that relatives were determined to keep fighting.
"It is important that the British government realise that the victims of collusion will not rest until the truth comes out," he said.
"The issue of collusion and the legacy it has left needs to be on the agenda of the British Government and those parties in the review.