It has now emerged why there were conflicting reports about the state of the mobile phone network last July 7th 2005, in the aftermath of the terorist bomb attacks in London:
Report of the 7 July Review Committee (.pdf) of the Greater London Assembly.
"London's telephone networks experienced unprecedented volumes of traffic. Vodafone experienced a 250 per cent increase in the volume of calls and a doubling of the volume of text messages. There were twice as many calls on the BT network as would normally be the case on a Thursday morning. Cable & Wireless handled ten times as many calls as usual to the Vodafone and O2 networks - 300,000 calls were placed every 15 minutes, compared to 30,000 on a normal working day. O2 would normally expect to handle 7 million calls per day. On 7 July, 11 million calls were connected - 60 per cent more than usual - and this does not include unsuccessful calls."
This was all entirely predictable, given the experiences of New York on Spetember 11th 2001, and the large scale electrical power outage of 28th August 2003 in South London
However, there is is only so much a mobile phone network operator can do to temporarily and marginally increase their network capacity in an Emergency e.g. "call gapping" to arbitrarily prevent a percentage of dialed calls from actually connecting, (which doubles the radio capactiy at a Cell Base Station, but results in lower call quality) and perhaps , turning off the Handset to Cell Base Station Encryption etc. Since none of their "critical national infrastructure" was actually out of action as a direct result of the terrorist bombs, it appears that the mobile phone network operators' emergency plans did not kick in immediately, as they expected their networks to cope ok.
What is not acceptable is the apparent lack of coordination between the Metropolitan Police "Gold Command" who were nominally in charge of the emergency, and the City of London Police (presumably one of the "Silver Commands"), who for their own understandable reasons got the O2 mobile phone network to implent Access Overload Control (ACCOLC) , in an area of about 1 kilometer around Aldgate Tube station i.e. covering much of the City of London, in spite of the decision by Gold Command not to impose ACCOLC in the same area at the request of the London Ambulance Service.
Apparently the Emergency plan does not require the mobile network operator to seek confirmation from Gold Command for initiating ACCOLC,
What is the point of having a Gold / Silver / Bronze" emergency incident command and control structure if it is not actually in command ?
It also emerged that nobody appears to be sure how many key emergency workers are actually carrying mobile phones equipped with the specially issued SIM cards, which would allow their phones to work, when the general public is excluded from the network under ACCOLC.