The coroner in charge of inquests into the 1974 Birmingham pub bombings has announced plans to appeal against a High Court ruling on the scope of the hearings.
Sir Peter Thornton QC is to seek permission to take the "perpetrator issue" raised by relatives of those killed to the Court of Appeal, delaying a pre-inquest hearing scheduled for next month.
In a ruling handed down last week after bereaved families sought a judicial review, two High Court judge ordered the coroner to re-consider his decision to exclude investigations into the identity of suspects.
But Sir Peter has now said he intends to ask the Court of Appeal to rule on the "vital" issue to avoid delay and uncertainty in the future.
A spokesman for the inquests said: "The coroner has considered carefully the High Court judgment handed down last week on the scope of the inquests.
"The judgment concerns the extent to which these inquests, which are not criminal proceedings, can investigate and seek to identify those individuals who were responsible for the tragic events in Birmingham 43 years ago.
"This is a complex matter about the purpose of an inquest and the approach of a coroner to setting the boundaries of his, or her, investigation.
"The questions raised by the judgment are vital to the inquests into the deaths of the 21 people who died as a result of the bombings and are also of general public importance."
The spokesman said the coroner considered that "clarity and certainty" are required so the work of the inquests can continue to proceed effectively.
The statement continued: "The coroner regrets that this application for permission to appeal will mean that the inquests cannot proceed to public hearings at this time."
"Work will continue on matters that are not related to the issues considered in the High Court judgment. The coroner will continue to work with the families, the other Interested persons at the inquests, and potential witnesses."