The alleged bugging of an MP's visit to a jailed constituent raises questions over "who is in charge" of surveillance in the UK, shadow home secretary David Davis has said.
His comments came after it emerged that Home Office and Ministry of Justice officials were told of the the incident in December.
Home secretary Jacqui Smith and justice secretary Jack Straw, however, were apparently not alerted until reports in the Sunday Times this weekend.
Conversations were said to have been recorded between 2005 and 2006 at Woodhill Prison between Labour MP Sadiq Khan and Babar Ahmad, who is in prison awaiting extradition to the US.
He is accused of running websites supporting Taliban and Chechen terrorists.
Police are entitled to record prisoners' communications if they have approval, but the bugging of MPs' conversations with their constituents is forbidden by the "Wilson doctrine".
Davis told Tuesday's BBC Radio 4's Today programme it seemed that Straw and Smith were "not in charge of their departments".
"Why was this allowed to happen without any ministerial knowledge?" he asked.
"Why, when it was discovered in December, why didn't tell Jack Straw or Jacqui Smith?"
Davis has claimed he wrote to the prime minister almost two months ago warning he suspects and unnamed MP was being bugged, but Downing Street has denied receiving any such letter.
On Monday Straw told the Commons that chief surveillance commissioner Sir Christopher Rose had been asked to start an inquiry to establish whether conversations between Khan and Ahmad had been recorded.
It has been reported that the bugging was carried out by Mark Kearney, a former sergeant with Thames Valley Police currently facing prosecution for allegations of wilful misconduct in a public office.
He said in court documents he was under pressure from the Metropolitan Police to carry out surveillance on the meeting between the MP and his constituent.
Questions have also been raised over whether the "Wilson doctrine", laid down by the former prime minister in 1966, applies in cases – such as this – where the interception could be approved by police and did not need ministerial authorisation.
6 February 2008