Concerns over the resilience of the Airwave emergency services radio system have led to calls for a major review, and a postponement of plans to switch off analogue communications next year.

A Computing investigation has revealed worries about the ability of the £2.9bn system to provide adequate backup in the event of failure.

We can reveal that the some Greater Manchester police officers had to revert to mobile phones and the old analogue during a fire in a BT tunnel in Manchester in March.

According to a force spokesman, the fire meant that 'the Airwave system was disrupted.'

Although Airwave operator O2 insists it was a 'minor' incident that was resolved quickly, it has added to worries about back-up when all the emergency services are using the system.

Patrick Mercer, Conservative shadow Homeland Security Spokesman, says the incident was extremely worrying and called for a thorough review of the network

'In the light of this incident there would appear to be a need for a review of the equipment and services that are being used to ensure that there is an adequate backup to protect both the public and the emergency services,' he said.

The Fire Brigades Union has added to worries with a report that warns: 'there is significant advice that a single replacement digital network would leave the emergency services dangerously vulnerable.'

Computing understands that the ambulance service has also referred concerns over the system's resilience to the Department of Health.

Police are understood to have raised the same issue but were told by the Police IT Organisation that their concerns should be with the delivery of the service.

A spokesman for the Police Federation lent weight to the calls for improved robustness.

'In the event of Airwave networks not being operational, the Police Federation would like to see emergency and contingency plans put in to place to minimise risk to officers and the disruption to public service,' he said.

Airwave has confirmed that it is looking into ways of improving the resilience of the system to satisfy the concerns of the ambulance service.