Police swoop on MP ‘wasn’t lawful’

Leading QC Geoffrey Robertson said the raid was therefore unlawful.

He said: "It was an unlawful search and Mr Green should be able to obtain substantial damages from the Metropolitan Police for this ignorant blunder."

Detectives who searched through files and removed computer equipment relied on a letter from a senior Commons official for authority to carry out the raid.

Scotland Yard was insisting that the written consent of the Serjeant at Arms, Jill Pay, was enough to give them full authority. However, some constitutional experts said the explicit consent of the Speaker, Michael Martin, would have been required. Until today Scotland Yard had maintained that it had search warrants for all four addresses that were searched last week.

But speaking to the Metropolitan Police Authority, acting commissioner Sir Paul Stephenson said only three warrants were actually obtained.

A Met spokesman added: "The written authority to conduct a consensual search was obtained from the Serjeant at Arms."

Mr Robertson said the Speaker and Mr Green himself would have had to give consent for the search in the absence of a warrant. He argued that parliamentary privilege overrode ordinary laws.

The disclosure adds more pressure on the Speaker to explain why police were allowed to simply enter the office of an elected Member of Parliament. Without a warrant, he could simply have refused entry - just as any householder can deny police permission to search their home or office.

A Tory spokesman confirmed that the MP had not given his consent but Mr Martin's spokesman refused to answer questions. Scotland Yard sources insisted Ms Pay's permission was enough and said that she took legal advice before writing her letter.

One constitutional expert said the police were right and that it would have been wrong for the Speaker to stand in their way.

A Scotland Yard source said that under the Police and Criminal Evidence Act, a search warrant cannot be obtained if consent for a search had already been given.

Home Secretary Jacqui Smith lashed out at the Tories for lacking "respect" for the law. She angrily dismissed suggestions that she was not being straight with the public over what she knew about the investigation before Mr Green's arrest last Thursday.

A former chief prosecutor attacked the handling of the police inquiry. Sir Ken Macdonald, who stood down as Director of Public Prosecutions just weeks ago, told Newsnight he seriously doubted whether any convictions would result.

He also suggested the Met had blundered by failing to properly consult with the Crown Prosecution Service. Sir Ken said the Met should have consulted the current DPP, Keir Starmer. "If the police proceed in a case which is this sensitive without consulting prosecutors, then things will go wrong," he told the programme.