The Bloody Sunday families have issued a statement in advance of today's 29th anniversary march in memory of those killed, saying they are losing faith in the new tribunal's ability to get to the truth.
The families said they fear a second whitewash unless the British authorities are more open about their role in the massacre.
They expressed grave concern at the fact the British Ministry of Defence still refuses to be legally represented at the Saville inquiry and insists it has no case to answer.
That stand comes despite the fact they were responsible for the 1st Paratroopers, who opened fire on the fateful day in 1972.
The campaigners for justice in this case added they believed the British excuse, that a 'computer glitch' destroyed crucial evidence such as photographs, film footage and weapons, was an insult to everyone's intelligence.
Today's march in Derry will follow the same route and retrace the steps of the original civil rights demonstration, which was fired upon by British soldiers on Bloody Sunday, killing 14 people and seriously wounding 14 others.