Simultaneous loss of all fixed and mobile forms of communication

Impact 5
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risk indicator
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Impact & Likelihood
Impact key
5 Catastrophic
4 Significant
3 Moderate
2 Limited
1 Minor
Likelihood key
5 >25%
4 5-25%
3 1-5%
2 0.2-1%
1 <0.2%


The simultaneous loss of access to all fixed and mobile forms of communication is a form of systems failure that may occur as a result of severe weather. Major storms can cause significant disruption to broadband and mobile infrastructure potentially leading to outages for customers. Ofcom places a regulatory obligation on communications providers to take 'all necessary measures to ensure uninterrupted access to emergency organisations' for their customers, and has issued guidance to protect access to emergency organisations when there is a power cut at the customer’s premises.


This scenario assumes that all mobile and fixed-line (landline and internet) connections would be lost immediately as a result of a hazard materialising, such as a severe storm or flooding. The incident would affect one region, with most fixed-line connections remaining offline for several days due to a lack of power at the customer premises and damage to overhead cables. All mobile connections in the region would be disabled temporarily until mobile network operators deploy back-up generators to mobile cell sites.

Key assumptions

The risk is cause-agnostic and only considers public communication networks (not private networks). It assumes that most domestic premises affected do not have a back-up power supply and the resilient communication systems used by emergency services would not be affected.


Variations include the scale, services impacted, and the length of disruption. Recent severe storms Arwen and Eunice are recent examples of a similar scale event. Storm Arwen (November 2021) was most severe, resulting in millions of customers losing access to mobile and fixed-line connections.

Response capability requirements

All affected customers would be unable to call 999/112, requiring a full response from Local Resilience Forums and their devolved administration equivalents, government, and local authorities to mitigate against this. Proactive checks for the most vulnerable would be required, especially if they do not have any alternative means to communicate. Resilient communications would need to be established for responders (either via long- range radio or satellite comms); or an alternative power source will be required to power communications equipment.


Telecommunication equipment would be very quick to recover, providing the cause of the outage does not persist. Flooding may take longer to recover from as most affected equipment would need to be replaced. Additionally, telecoms equipment is often replaced every 2-5 years and so the sector is well-practised in the quick replacement and repair of equipment, or rerouting of traffic across the network, to minimise disruption to the network. Engineers and recovery assets are also dispersed evenly across the UK, meaning response times would be similar – regardless of what region is affected.