The West Midlands Police officer leading the investigation into the alleged terror plot was reported yesterday to be furious over suspected Whitehall leaks about the inquiry.

Assistant Chief Constable David Shaw was said to be "seething" and angry that the inquiry had apparently been "hijacked" by the Government, according to the Mail on Sunday.

It quoted a source, said to be close to Mr Shaw, as saying: "He is angry that while he had played a straight bat, there are others in Government departments who, without asking him, briefed the media about his inquiry."

It was also claimed he was increasingly frustrated that anonymous briefings may be impeding his officers' efforts to gather evidence. The report said that at one point, details of the operation were being broadcast while one of the suspects had still to be found.

The MoS quoted the source saying: "He feels the inquiry has been hijacked by those who don't have to live – as he does – with the direct consequences of what they say publicly. To my knowledge, he hasn't speculated as to what motivated these people to brief the media but it's really rather obvious that there are various agendas at work here."

Last Thursday, West Midlands Police was given a further seven days to hold the nine men after applying for an extension at Coventry Magistrates’ Court. Forensic specialists have been scouring 15 properties in Birmingham which were seized during Wednesday’s operation. The nine suspects, British men of Pakistani descent, have been detained on suspicion of the commission, instigation or preparation of acts of terrorism. They will remain in custody at Chase Avenue police station in Coventry.

Police can now detain terror suspects for 28 days without charge. However, during that time they have to apply for a series of extensions. The Midlands Counter Terrorism Unit leading the investigation - codenamed Operation Gamble - has so far refused to disclose any details about the inquiry, and Mr Shaw has not commented on the operational details.

At a briefing last Friday at West Midlands Police headquarters, he said: "I am acutely aware that members of the community are confused and bewildered about what is being said by the media about the investigation and their communities.

"I wish to make clear to the people of the West Midlands that I have not given any confirmation of the ethnicity, faith or religion of those we have in custody, I have not provided details of the nature of the allegations these men are facing and I will not be.

"Despite certain labels that have been given by the media, in its purest and simplest sense we are investigating criminality."