The naming of possible suspects at fresh inquests into the 1974 IRA Birmingham pub bombings has been ruled out by a coroner.
Senior coroner Peter Thornton said the issue of perpetrators should not be included as he published his written ruling on the scope of the hearings, due to begin later this year.
21 people died and hundreds were injured when two bombs exploded in two Birmingham pubs in November 1974.
Bereaved relatives of some of the 21 victims had called for the widest possible scope in their bid for "truth and justice".
Julie Hambleton, whose older sister Maxine died in the double bombings, had said "we may as well not bother having an inquest" if the issue of suspects could not be examined.
Ms Hambleton said the group Justice4the21, which she represents, received the ruling with "anger and regret".
In a 15-page ruling, Mr Thornton, the former chief coroner, said: "To permit the identity of perpetrators to be within scope would be seen to be taking on the role of a proxy criminal trial. If this were to result in a determination identifying those responsible for the attacks that would, in my judgment, be unlawful."
He added, given the "sheer size and complexity" of any investigation into who may have carried out the attacks, it was not the role of the inquest.
The judge added it would "be invidious for the inquests to attempt to do", what various criminal and case reviews investigations had tried and failed to do over the past 43 years.
He said: "The approach would inevitably be piecemeal and incomplete, mostly reliant upon persons named in books and the press, mostly by journalists."
Mr Thornton added any investigation into the perpetrators was "a task entirely unsuited to the inquest process", given its "limited resources".
He also ruled out the reactions of the emergency services on the night of the bombings forming any part of the evidence, despite the relatives' asking it be included.
However, Mr Thornton said evidence could be heard on the issue that police may have been tipped off twice about the possibility of a bomb attack, in the run up to the blasts.