Cyber attack - electricity infrastructure

This risk is featured in the full matrix, representing the averages of multiple different scenarios presented together in the ‘cyber attacks on infrastructure’ category.

Impact 5
risk indicator
ID 11
Risk theme Terrorism
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 National Electricity Transmission System (NETS) transports electricity across Great Britain. A cyber attack may involve encrypting, stealing or destroying data upon which critical systems depend or disruption to operational systems leading to the failure of the NETS. A failure of this system has the potential to severely disrupt all other critical systems, resulting in greater consequences than typical utilities failures. Great Britain has never experienced a nationwide loss of power and the likelihood is low, however similar events have occurred internationally due to natural hazards, rather than cyber attacks. Great Britain has
one of the most reliable energy systems in the world and maintaining a secure electricity supply is a key priority for the government.


The reasonable worst-case scenario is based on a malicious cyber attack on a critical electricity system, leading to a total failure of the NETS. All consumers without back-up generators would lose their mains electricity supply instantaneously and without warning. A nationwide loss of power would result in secondary impact across critical utilities networks (including mobile and internet telecommunications, water, sewage, fuel
and gas). This would cause significant and widespread disruption to public services provisions, businesses and households, as well as loss of life.

Key assumptions

For the purposes of the reasonable worst-case scenario it is assumed that the event occurs in winter when there is a high demand for electricity.

Response capability requirements

There would need to be preparations in place to support
wider recovery and the continued operation of multiple sectors. This includes functioning telecoms, emergency services and fuel distribution. It would be vital to ensure that fuel is available
to priority users and can be distributed quickly across the country as required. To support the immediate aftermath of the incident, resilient communications systems, humanitarian assistance and victim support should be in place.


Within a few hours, small pockets of consumers would be gradually reconnected with intermittent power supply, with a significant proportion of demand being reconnected within a few days to create a stable ‘skeletal network’. Full restoration could take up to 7 days. However, depending on the cause of failure and damage, restoration of critical services may take several months. A cyber attack could mean that recovery takes longer than expected, depending on the sophistication of the attack and damage to the system.