A report into the 7 July 2005 London bombings has said the lack of a digital radio network hampered the efforts of emergency service rescue teams, which were unable to communicate properly between the sites of the explosions underground, colleagues at ground level and control rooms.
The London Assembly's 7 July Review Committee report said it is "unacceptable" that the emergency services are still not able to communicate by radio when they are underground, 18 years after the official inquiry into the King's Cross fire recommended action to address the problem.
A project, called Connect, to enable emergency services personnel with digital radio handsets to communicate underground and from below surface to ground level is currently two years behind schedule but Transport for London (TfL) says it will be completed next year.
The lack of a digital radio network meant that many senior managers among the main emergency services, and the London Ambulance Service in particular, were forced to rely on using already overloaded mobile phone networks to communicate in the aftermath of the explosions.
Martin Flaherty, director of operations at the London Ambulance Service, told the committee: "We have accepted that we have become too reliant on mobile phone technology as a communication tool, and it is clear now that it cannot be relied upon in a complex major incident scenario."
This had a direct impact on rescue efforts with requests for further ambulances, supplies and equipment by London Ambulance Service personnel at the scenes of incidents failing to get through to the main control room. They were also unable to receive instructions as to which hospitals were still receiving patients.
The London Assembly report concluded: "It is essential that London's emergency services are equipped with digital radio equipment so that they no longer have to rely on mobile telephones to communicate between the scenes of major incidents and the control rooms."
The scale of the mobile network overload is revealed in the report. Vodafone, for example, experienced a 250 percent increase in the volume of calls and a doubling of the volume of text messages. Across all networks on 7 July, 11 million calls were connected — 60 percent more than usual. This figure doesn't include unsuccessful calls.
Despite this network overload, the emergency services did not invoke the Access Overload Control (ACCOLC) system — apart from a 1km-square area around the Aldgate incident — which restricts mobile network access to the police, fire and ambulance personnel.
One of the reasons ACCOLC was not activated was that key emergency services personnel who were not carrying specially enabled telephones would not have been able to make or receive any calls.
The London Assembly report said: "This is clearly a major flaw in the system: there is no point in having the technology to enable key people to communicate with each other if the relevant authorities do not make sure that the right people are in possession of that technology."
London Underground's "antiquated" radio systems were also criticised after they failed to work on any of the three affected tube trains on 7 July, preventing direct communication from the trains to either the emergency services or TfL's control centre.
The report said the 20-year timeframe for the completion of TfL's £2bn PFI project for the rollout of a digital radio system underground on the tube needs to be "significantly reduced" and a feasibility study undertaken to assess potential interim technology solutions.
TfL said it welcomed the report and the London Resilience Network, which represents the city's emergency services, said some of the communications issues raised by the London Assembly report have already been recognised and acted upon.