The UK government may have wasted more than £300m on the Airwave digital radio system, according to the Public Accounts Committee.
The Committee's report described the £1.5bn national network as "more sophisticated and expensive" than necessary.
While the new Terrestrial Trunked Radio-based system will allow different police forces to communicate with each other, they cannot use it to communicate with local fire services.
The report claimed that Airwave will cost £300m more than a series of localised digital systems wanted by Police Authorities.
Despite police preferences, the government has insisted on the adoption of Airwave at a cost of £1.5bn over 19 years.
It is now a decade ago that a Home Office review recommended that police and fire services adopt compatible radio systems.
But the Committee warned that the day when emergency services within a particular area could communicate easily with each other during major incidents is "still a long way off".
There are also questions over the effectiveness and safety of the handsets. Scientists have pointed out that the devices pulse at 17.6MHz, which they believe is too close to the 16MHz at which brain signals operate.
In April, the National Audit Office labelled Airwave a risky project, while 30 police officers claimed that the handsets triggered illnesses following pilot schemes in Lancashire and North Yorkshire.
Airwave has since been adopted by seven police authorities, but ambulance and fire services are thought to favour rival Tetrapol technology.
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