The department has appealed a decision by the coroner of the 7/7 inquests that she could not hear evidence in closed sessions.
The Home Office will challenge that decision by judicial review.
A spokesperson for the department said: ‘The Government has made clear that it welcomes the coroner’s inquests. We hope that they will allow the families of the victims to get to the bottom of the tragic events of 7 July 2005.
‘This does not mean, though, that we will put lives at risk and undermine our national security by not protecting sensitive material. Therefore, having carefully considered the coroner’s ruling on closed evidence, we have decided to appeal.’