Permanent software fix applied to BT 999 platform

BT introduced a permanent software configuration fix for its 999 platform and enhanced the process for transitioning to its backup system, following a technical fault on Sunday 25 June 2023 that disrupted the Public Emergency Call Service (PECS) across the UK¹. The measures are set out in a Post-Incident Review into the disruption, which states that a permanent software configuration fix was introduced by 29 August 2023¹.

The review describes the fault as a complex software issue related to a "caching" mechanism used by the software for handling 999 emergency calls¹. It divides the incident into three phases: disruption between 06:24 and 07:31 (1 hour, 7 minutes), when a significant proportion of calls disconnected during transfer from the BT call handler to the relevant emergency authority control room; denial between 07:31 and 08:50 (1 hour, 19 minutes), the most serious period, when all callers were unable to connect because of a procedural failure by BT in activating its backup system; and delay between 08:50 and 16:56 (8 hours, 6 minutes), when the service was operational but some calls were handled on the backup system with reduced functionality, so calls took longer¹.

During the incident, a total of 9,641 unique callers were unable to access the emergency services via 999 or 112, and many more were delayed or disrupted¹. BT assesses that alternative PECS services provided to a very small number of customers, such as Video Relay, SMS and eCalling, may also have been affected¹. The review states that, to date, there are no confirmed reports by the emergency authorities of serious harm done to members of the public as a result of the disruption, although this will continue to be kept under review by those authorities¹. It also states that 253 unique callers were not able to be contacted¹.

The review says the incident marked the first nationwide loss of 999 in over 86 years since the inception of the PECS in 1937¹. It records that in 2022 the public made 35 million calls to the service, 53% of which were for an ambulance, 44% for police, 3% for fire and rescue, and less than 1% for HM Coastguard¹. BT filters approximately 30% of calls, identified as repeat calls, misdials or nuisance callers¹. The PECS partners make a total of 113 separate entities: 45 territorial police forces (and 3 special police forces), 49 fire and rescue authorities, and 14 ambulance service trusts¹.

The review also records that, after collective agreement from all PECS partners on 17 July 2023, a nationwide 999 Strategic Incident protocol was established¹.

Why it matters for households

The 999 service is the primary means for the UK population to seek help in emergencies, and the review states that it is essential that the system is resilient and remains available without interruption¹. The incident affected callers across the UK, and the review notes that during the denial phase all citizens dialling 999 would have failed to connect¹. It states that until approximately 15:45, when the government released a statement to the media, the public were advised to use the non-emergency numbers 101 and 111 to seek emergency support from police and ambulance services respectively in the absence of 999, but that this is not applicable for some parts of the UK such as Northern Ireland¹. Households can keep emergency and non-emergency numbers on paper using the guide to emergency and non-emergency numbers, and the staying informed hub covers how official warnings and alerts reach the public.

What happens next

The review sets out recommendations on strengthening the end-to-end 999 PECS system and on preparedness to respond to future 999 PECS incidents¹. It states that its findings will have no bearing on any later findings by Ofcom, which is investigating compliance with its General Conditions of Entitlement and applicable sections of the Communications Act 2003¹. The review also refers to BT's own internal investigation, published on its website on 29 June¹.