Home Secretary Jacqui Smith and a Home Office mandarin is to be quizzed by MPs over the controversial arrest of Tory frontbencher Damian Green.
Ms Smith and Home Office Permanent Secretary Sir David Normington will appear before the Home Affairs Committee, which is looking into the investigation surrounding Mr Green's arrest.
He was detained in November last year by police investigating a series of leaks from the Home Office. The operation, which included the search of Mr Green's Commons office, sparked widespread condemnation and has led to a review of parliamentary procedures.
Tuesday's committee session comes after it emerged that the Home Office was not notified in advance that Mr Green was to be arrested.
Police informed officials only that they were intending to search the Tory immigration spokesman's parliamentary offices, not that he was to be taken into custody, according to sources.
Delays in the message being received also meant senior civil servants were unaware of the raid until after it began. The revelations show the extent to which the Home Office was kept in the dark over the investigation.
The inquiry, which is led by Scotland Yard Assistant Commissioner Bob Quick, has already faced questions over the methods it used.
A review by British Transport Police chief constable Ian Johnston has raised concerns over whether the approach to the investigation followed best practice and policy guidelines.
Mr Quick was forced to apologise and withdraw claims he made suggesting the Tories were seeking to undermine his inquiry.
Anti-terror police raided Mr Green's home and parliamentary offices on November 27. He was arrested and held in custody for nine hours before being bailed. The Crown Prosecution Service is expected to make a decision on whether or not to charge both Mr Green and Mr Galley in the coming weeks.
