The NAO report, published yesterday (11 April), stated that while the procurement strategy was well thought through, it was not delivered in full.
In fact, the report found that the cost of equipment for implementing the system varied considerably because of different requirements around the country. For example, the price of a switch varied from £300,000 to £1 million.
The NAO said PITO, the Police IT Organisation, had been unable to provide it with the costs and, as a result, had lost the opportunity to establish a robust database of costs for use in the future.
In the report, the NAO said that if such a database were kept regularly updated, it would have assisted in pricing future changes to the service and in future benchmarking exercises.
The NAO considered that PITO had taken best practices for project management in adopting a modular approach to the rollout which involved testing at each stage, but criticised its handling of the six-month pilot phase in Lancashire.
The report stated that during the pilot, police officers were frequently dropped off the network without warning and had to reboot their radios.
The NAO said the problem affected up to 2% of calls. The impact of the bug, according to the NAO, was that officers could expect this to happen at least once on every shift. This had important implications for safety, as officers did not always know that they had been dropped off the network and were, therefore, out of touch with their control room.
In spite of these limitations on the system, the rollout is still going ahead. According to the NAO report, Airwave will involve additional expenditure of some £300m over the contract period in order to make the system acceptable for English and Welsh forces
In the past few months the service has been under scrutiny regarding coverage around the country, and questions have been raised over possible public heath risks from the radio spectrum Airwave uses.