The question in plain English
Britain's essential services depend on one another. Electricity networks need communications to see faults and direct repair teams. Mobile and data networks need electricity and backup fuel. Fuel deliveries need power, communications and drivers.
This study asks a simple question:
If electricity, telecommunications and fuel services were disrupted repeatedly over several weeks, could repairs keep up — or would unrepaired damage build while failures in one service made the others harder to restore?
The study does not predict an attack or estimate how likely one is. It starts with hypothetical sequences of disruption and tests how the services recover.
The electricity and fuel findings apply to Great Britain, not Northern Ireland, which has separate arrangements. Some telecommunications evidence is UK-wide.
What was tested
A computer model represented electricity, telecommunications and liquid-fuel distribution across four invented regional types. The regions are analytical examples; none represents a named part of Britain.
The same incidents were run through four versions of the system:
| Version | What it tests |
|---|---|
| A — sectors restore separately | A comparison case using the study's declared resource assumptions |
| B — services affect one another's repairs | For example, communications loss slows electricity repair |
| C — sectors share scarce resources | For example, two sectors need the same drivers or temporary generators |
| D — both effects together | Services affect repairs and also compete for shared resources |
Because every version receives the same incidents and the same total resources, the differences reveal which cross-sector effect is doing the damage.
Four of the six resource capacities in the model are scenario values, not measured Great Britain capacities. The model can show how the system behaves under those assumptions. It cannot establish Britain's actual level of preparedness.
What the study found
1. One service slowing another's repairs is the largest effect
The strongest result is not that sectors compete for the same equipment. It is that the loss of one service can reduce another sector's ability to recover.
Examples include communications failure making faults harder to see and repair teams harder to direct; electricity loss disabling telecoms equipment and fuel pumps; and fuel disruption restricting vehicle movement and backup generation.
In the model, these effects caused much larger service losses than competition for shared repair resources.
2. Sharing helps, but what is being shared matters
The model tested two different kinds of sharing.
Sharing resources between regions within the same service, such as moving electricity repair crews from one area to another, improved recovery across every allocation setting tested.
Sharing resources between different services, such as fuel-tanker drivers or temporary generators, also helped under many conditions. But when several services needed the same pool at once, that benefit could diminish or turn into competition.
Even when a shared pool was fully occupied, sharing could still produce a better result than dividing the same capacity permanently between services. "Fully used" and "harmful" are not the same thing.
3. The original "multiplying damage" hypothesis was not supported
The study began with a stronger expectation: that services slowing one another's repairs and sectors competing for resources would reinforce each other, making the combined damage greater than the two effects added together.
That did not happen in the main physical results. The combined effect was small and usually slightly less than the sum of its parts. One apparent exception — more generator refuelling — proved beneficial: more fuel support was delivered while unmet demand and service impairment fell.
The study therefore supports the importance of cross-sector dependencies, but not the claim that the two mechanisms multiply the harm.
4. Cross-sector competition appears much later than the first repair backlog
The model compared two points: when half of the separate-restoration runs first stopped keeping up with incoming disruption, and when shared resources became fully committed across sectors.
The second point occurred at about 3.8 times the disruption level of the first. The plausible range is 3.2 to 4.7 times, based on uncertainty around the first point only. In simple terms, the model had to experience roughly four times as much repeated disruption before shared resources became the limiting problem as it did before ordinary repairs first fell behind.
This is a result within the declared model. It is not a measured national danger threshold.
What remains unknown
The public evidence does not reveal the size of the two shared resource pools that would determine where Great Britain sits relative to that boundary:
- drivers actually available both for ordinary fuel delivery and for generator refuelling during the same emergency;
- temporary generation actually available and deployable across sectors.
National driver totals do not answer the first question, and commercial generator hire fleets do not automatically form one coordinated emergency pool.
This does not show that Britain lacks capacity. It means an outside analyst cannot determine whether capacity is ample, marginal or insufficient from public information.
Ofcom's own technical report does provide useful evidence on mobile backup: around one in five UK mast sites had at least one hour of backup, and around one in twenty had at least six hours. These figures do not show how much backup every other site holds. Ofcom's estimate that about two-thirds could still make emergency calls during an outage of up to one hour depends on phones being able to roam onto another available network; it is not a count of operational masts.
A widely quoted figure for telephone lines used in utility monitoring remains excluded because it combined gas and electricity and provided no electricity-only count.
The policy gap
Existing arrangements cover important parts of the problem, but not the exact event modelled here.
- Electricity customers may be entitled to compensation when supply is not restored within specified periods. These rules do not state how much restoration capacity exists.
- Great Britain has an Electricity System Restoration Standard for a total or partial shutdown of the transmission system. Its capability deadline, 31 December 2026, had not arrived when this study was prepared. Separate resilience requirements for designated generators, including 72-hour arrangements, have applied since September 2024.
- The study found no published rule for this middle case saying how quickly the three services should recover together or what shared resources must be available.
This is not evidence that restoration planning or cross-sector coordination is absent. Ofcom reports active joint work between telecommunications and electricity bodies. The gap is the absence of an identified joint restoration target backed by specified shared resources.
What follows from the findings
The results point to four practical priorities:
- Protect the systems that repair teams need — power, communications, fuel and operational visibility — because this is where the largest modelled effect occurs.
- Do not divide shared resources automatically in the name of resilience. Test where sharing stops helping before changing how pools are organised.
- Measure the genuinely shared driver and temporary-generation pools. Aggregate, non-site-specific figures would be enough to locate the capacity boundary more credibly.
- Exercise sustained cross-sector recovery below the national-shutdown threshold, including what happens when several services need restoration support together.
Conclusion
In this model, the main danger is that failure in one essential service slows the repair of another. Sharing scarce resources usually helps, and the expected multiplying effect between dependency and competition was not found. Whether Great Britain is close to the point where shared resources become a serious constraint cannot be established because the necessary capacity figures are not public.
What this study does not claim
It does not estimate the probability of war or attack, attribute any past incident, or conclude that Great Britain has insufficient restoration capacity. It does not claim that customer protections or restoration planning are absent. Its simulated service figures are comparison measures created for the model, not real-world person-days.