London Ambulance Service has suffered seven hours of unplanned downtime on its 999 call management system since a software upgrade one month ago.
A spokesman for the service said a database software upgrade on 29 July caused disruption to the system. The worst incident meant the system was not performing properly for three hours, and control centre staff had to resort to paper-based processes.
Although the problems have largely been resolved, a spokesman admitted there were still periods of poor performance for up to 20 minutes.
"During the downtime we can revert to taking information on calls using pen and paper and revert to a manual system to assess priority, which can be more time-consuming," he said.
The London Ambulance Service has had IT problems in the past. In 1992, a succession of glitches following the introduction of a computer-aided dispatch system led to delays of up to three hours in ambulances reaching emergencies.
Following the 2005 London terrorist bombings, the service had to revert from mobile phones to pager technology due to the lack of capacity on the cellular network.
Daniel Dresner, research manager at the National Computing Centre, said, "People should not underestimate the amount of testing needed." Where a new application is safety-critical, a very good regime is needed to assess risk and review results, he added.
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