The inquiry into riots at a detention centre for asylum seekers must be made public, shadow home secretary Oliver Letwin has demanded.
The blaze destroyed half the centre
He has asked Home Secretary David Blunkett to put the investigation into the disorder and fire at the Yarl's Wood centre last year under public scrutiny.
Half of the centre in Bedfordhire was destroyed by the blaze, but after a three-month trial costing more than £1m, no one has been convicted of arson.
The Prisons and Probation Ombudsman, Stephen Shaw, is conducting an inquiry into the incident.
Mr Letwin, in a letter to the home secretary, said: "Will you now agree to publish the Home Office's existing report into the incident, and agree also to make the inquiry by Stephen Shaw a public one?
"I am sure you will agree that the public have every right to a full explanation - and these measures are clearly the way to provide such an explanation."
But a Home Office spokesman told BBC News Online: "Stephen Shaw's job is to report to the home secretary. Details of what will be published will be decided when the report is received."
Nearly 30 workers at the centre are suing the company in charge of the centre, Group 4, for post-traumatic stress and physical injury they claim was a result of the violence.
Group 4, which is part of the Group 4 Falck group, was branded a "laughing stock" in court, and the judge said the firm was ill equipped to deal with the violence.
But the company rejects this claim and says it has offered emotional support to staff who were affected.
Two asylum seekers were jailed for four years on Friday for violent disorder.
Twelve men escaped and are still at large, while the centre is only partially reopening in September.
The local MP, Alistair Burt, has also called for the inquiry into the riot to be held in public.