Home Secretary Jack Straw has pushed through a 19-year £2.5bn national, secure digital radio network contract for the police, despite fears that the cost might hit front-line operations.
Catherine Crawford, executive director of the Association of Police Authorities (APA), warned that "without new money, some authorities will have to reduce staff numbers to fund the new system".
The Quadrant consortium, led by British Telecom, with Motorola, Nokia and TRW, will pilot the system in Lancashire from September. It will then be rolled out across England, Scotland and Wales over the following five years.
Straw has told police authorities that 80% of the cost of the project will be "top sliced" from their central grant provision.
Straw said he hoped to get extra funding for the project in the Government's annual spending round. Whatever the outcome, forces will have to adopt the system as existing radio frequencies will be withdrawn at the end of 2004.
In December the Government asked police authorities to sign a non-binding letter of intent with the Quadrant consortium.
Thirty-nine of the 43 authorities in England and Wales agreed, but many included heavy qualifications about cost, length and future management of the contract.
West Midlands Police was one of four that refused to sign, despite a year of discussions involving the chief constable and director of technology with Quadrant.
An APA representative told Computer Weekly the £2.5bn cost would not provide a service usable by any police- force. "It is simply the infrastructure," he said.
"Forces will have to purchase additional services from a menu of BT offerings."
Jeff Parris, general manager of the project for BT, acknowledged police authority concerns, but emphasised the benefits of creating a unified nationwide radio service for all the emergency services.
"This is leading edge, not bleeding edge technology," said Parris.
"Once we have signed police forces, we want to push the system out to other blue-light services to provide genuinely joined-up emergency provision."
How the system will work
The Public Safety Radio Communications Project (PSRCP) infrastructure will consist of 3,000 radio base-stations providing coverage for the emergency services and public safety organisations throughout Britain and for aircraft up to 6,000 feet.
The base-stations are connected via landlines to a number of switches and from there to customer control rooms, using KiloStream/MegaStream links.
The system is based on the Tetra (Terrestrial Trunked Radio) and will operate in the 380-400MHz band.
Tetra "Voice + Data" provides voice mode and both circuit- and packet-mode data services. Speech is digitally coded at 4.8Kbit/s to maximise use of radio spectrum.
Speech signals are encrypted as standard, to prevent eavesdropping with an analogue scanner. Speech can also be encrypted end-to-end.
Group calls and broadcast calls are supported with fast call set-up times of about 0.5 seconds. Point-to-point calls can be made privately between individuals.
PSRCP will also support gateways into other systems such as PSTN/PTN interconnect; voicemail; and interoperability with older radio systems. Data calls may be made between mobile terminals or to and from central systems and databases.