The powerful new police agency dubbed "Britain?s FBI" refused to comment today after the Police Federation, union chiefs and serving officers questioned its effectiveness.

A spokesman for the Serious Organised Crime Agency (Soca) said the body would not speak on "matters of operational activity" or any of the issues raised in a television news report.

Soca?s silence comes after a spokesman for the union representing Soca officers told Channel 4 News that the agency was pursuing only a small fraction of the drugs cases referred to it by Customs.

And two Soca officers, speaking anonymously, suggested that some of their colleagues were demoralised because of excessive bureaucracy and insufficient policing work.

The chair of the Police Federation of England and Wales, Jan Berry, told the programme that the creation of Soca had left a vacuum between county forces tackling local crime and the new agency dealing only with the biggest cases.

She said: "There?s a whole raft of crime that?s now not even being looked at. It is not local enough to be treated by the local police force and not serious enough to be dealt with by Soca. To a certain extent, the criminals are benefiting from the lines drawn on maps."

She added that police forces were receiving many job applications from Soca officers seeking to return to conventional police work.

Soca was created last April following a merger of the National Crime Squad, the National Criminal Intelligence Service, and sections of HM Revenue and Customs (HMRC) and the Immigration Service.

It was intended to tackle organised criminals in areas such as hard drugs smuggling and people trafficking.

But one unnamed officer said: "I am achieving next to nothing in my job... Since Soca started, I haven?t taken on any new investigations and haven?t been asked to develop any intelligence to move into an investigation. I am just purely performing email, admin tasks.

"I think it is bureaucratic. Its management is top-centred, so people in the senior positions can?t make decisions without referring them back up to the executive directors."

Summing up the agency?s performance as disastrous, he said: "I and my team are under-utilised in comparison to what we were doing before. In my section of the organisation, morale is probably the lowest I have ever known it."

A second officer said: "I find it hard to find anything I could hang my hat on to say they were doing well. It is lacking in most areas."

Under the new arrangements, customs officers refer most cases of Class A drug smuggling to Soca to ask if it wants to investigate further.

According to Peter Lockhart, of the Public and Commercial Services Union, of 300 such cases offered to the agency so far, only "a handful... in the region of about 10 cases" have been taken up.

An unnamed "senior investigating officer" from Customs said: "The people at the ports and airports phone and offer the job to Soca. They wait for Soca to phone back. Sometimes this takes a very long time.

"We have had instances where a phone call on a Friday to Soca is not responded to until Monday, and the client ? for want of a better terminology ? is already back on the streets.

"Certainly, jobs which would have been taken on by Customs are not being taken on by Soca."

Nick Herbert, the Conservative spokesman on police reform, said that the report raised "serious issues of concern".

He said: "Soca has been in existence for less than a year but we will shortly need to subject its effectiveness to careful review.

"It is essential that this ?400 million new agency charged with leading the fight against serious crime is working properly."

A Home Office spokesman said: "Since becoming operational on April 1 2006, Soca has been focusing on enforcement work to reduce the harm caused by organised criminals ? including those involved in class A drugs, human trafficking and financial crime.

"Soca is using innovative methods to crack down on a wide range of organised crime and has been set strategic priorities by the Home Secretary which are reflected in its annual plan for 2006-07.

"An annual report on the exercise of Soca?s functions over this period will be published at the end of the financial year."