On May 12, 2025, a power outage caused significant disruption across several London Underground lines, including the Northern, Bakerloo, Jubilee and sections of the Elizabeth line. Electrical equipment was also affected, with lifts and escalators out of service at some stations. While TfL acted quickly to address the unexpected blackout to reduce the impact to travellers and normal service resuming across the network later the same day, the event follows other recent disruptions to the power network such as at Heathrow in March and in Spain and Portugal in April.
Fortunately, unlike the blackout earlier this year in Spain and Portugal, it appears that the London power disruption did not significantly affect the mobile network connection across the city. However, it does highlight the fact that mobile networks are no longer a luxury; they are critical infrastructure, essential to ensuring the resilience of transport systems and public safety. These incidents serve as a powerful reminder of the real-world implications of an unexpected power blackout in a society that relies on connectivity.
Today, over 25% of the London Underground network offers phone signal, with 31 out of 121 underground stations and tunnels equipped with mobile coverage. While recent efforts have accelerated the rollout of mobile connectivity, the difference between the level of disruption during the events in London and Spain demonstrate how vital reliable mobile networks are, not only for convenience, but for safety, communication, and operational response.
For MNOs, there are some important takeaways to consider in order to mitigate the impacts of power blackouts in future:
- Building a robust mobile network is non-negotiable: Critical transport environments like the Underground require reliable coverage that can endure or rapidly recover from infrastructure failures. Working with their partners, mobile operators must design, test and assure this service.
- Operational resilience depends on data: Data visualisation platforms can simulate power outage scenarios, helping operators understand and plan for the ripple effects of events on mobile connectivity. These tools are instrumental in identifying coverage gaps, prioritising upgrades, and informing network investment decisions.
- Collaboration is key: Mobile network providers must work in close partnership with public transport authorities and emergency services to future-proof the network. From testing network readiness to aligning on network deployment in high-priority zones, coordination will be the foundation of operational resilience.
As digital dependency grows, mobile networks must be treated as essential infrastructure, particularly in high-traffic, high-risk environments such as in London and other major cities. The examples in Heathrow, Spain and Portugal, and now London offer more than a lesson in power management; they underscore the need for proactive planning, real-time monitoring, and resilient network design.
How resilient is your network in a power blackout? Metricell supports network operators to visualise their infrastructure by providing real-time analysis of their connectivity data. Contact the team today to understand how we can help you with designing, deploying, testing and assuring your network.
