- Overhead lines on poles are most common in rural and suburban areas, where digging would be costly or impractical, while dense urban areas tend to use underground ducts.
- Openreach owns and maintains the bulk of the UK's poles, ducts and cables and carries out repairs on behalf of the retail provider you pay.
- Openreach makes its existing poles and underground ducts available to other providers under a Physical Infrastructure Access product regulated by Ofcom.
- Overhead lines are quicker and cheaper to repair but more exposed to wind, trees and debris, while underground cables are sheltered but harder to access for faults.
- As the network is upgraded to full fibre, Openreach reuses much of the existing pole and duct infrastructure rather than burying every new cable.
Overhead lines on poles are common in rural areas and quicker to repair but exposed to weather, while underground cables in towns are sheltered but harder to reach; Openreach reuses both as it rolls out full fibre.
Last reviewed: June 2026
Where overhead and underground lines are found
The choice between overhead and underground line was made long ago, largely on the basis of cost and geography, and it still shapes the network you connect to today. Overhead lines, carried on wooden poles, are most common in rural villages, on the edges of towns, and across open country where trenching would be expensive and disruptive. Stringing a cable between poles is far cheaper than digging a trench across fields or up a hillside, so the pole network dominates in low-density areas. Many suburban streets also use poles, particularly where the housing was built around an existing pole route.
Underground cables tend to dominate in dense urban centres and newer housing developments. In a city, ducts beneath the pavement keep cables out of the way of traffic, buildings and street furniture, and new estates are frequently built with ducting laid during construction. The result is a mixed national network in which a single property might be fed by an underground cable to a nearby pole, then an overhead dropwire to the house. The last short span into many homes, the dropwire, is very often overhead even where the wider route is buried.
This mixed pattern is why two neighbours can have very different connections to the same street. One house may take an underground feed straight into the wall, while the house next door is served by a pole and an overhead dropwire, simply because of how each property was originally connected. The economics that drove those decisions have not changed much: trenching remains the expensive option, and where an existing pole route or duct already passes a property, reusing it is far cheaper than laying anything new. For a household, the upshot is that whether your line arrives overhead or underground is mostly a matter of inherited local history rather than a choice you can readily make, and it is set by the route Openreach already has in place to your address.
Which type is more resilient
Neither type is simply better; each trades one set of risks for another. Overhead lines are exposed to the weather. High winds, falling trees, heavy snow and flying debris are the main causes of overhead faults, and a single fallen tree can take down a whole span. The advantage is visibility and access: an engineer can usually see the damage and reach it quickly, so repairs tend to be faster. Overhead lines are also cheaper to install and to replace, which is part of why they remain widespread across rural Britain.
Underground cables are shielded from wind and most surface hazards, which makes them less prone to weather-driven faults in normal conditions. Their weaknesses are flooding, ground movement, and the simple difficulty of access. When an underground cable fails, locating the exact fault and reaching it can mean excavation, road permissions and traffic management, all of which take longer than repairing an overhead span. Underground routes are also vulnerable to accidental strikes by third parties digging for other utilities. The most resilient outcome usually depends on the local hazards rather than the technology alone.
The mechanism behind these differing risks is worth drawing out. An overhead span fails most often through a sudden external force: a branch falls, a high-sided vehicle catches a low wire, or a storm brings a pole down. These events are abrupt and visible, which is exactly why they are quick to diagnose and frequently quick to make safe. Underground faults tend to develop differently, through water ingress at a joint, slow corrosion, or ground movement that stresses a cable over time, and they may show as intermittent noise or a gradual loss of service before a full failure. A property in a wooded, windy or coastal area may genuinely fare better underground, while a property on a flood-prone or frequently dug-up street may be more exposed underground than overhead. Resilience, in other words, is site-specific rather than a blanket property of either method.
Overhead vs underground line comparison
The table sets the two approaches side by side on the factors that matter most to households.
| Factor | Overhead | Underground |
|---|---|---|
| Common location | Rural and suburban | Urban and new estates |
| Main weather risk | Wind, trees, debris | Flooding, ground movement |
| Repair access | Usually quick and visible | Slower, may need digging |
| Install cost | Lower | Higher |
| Visual impact | Visible poles and wires | Hidden from view |
How each type is repaired
Repairs to both types are carried out by Openreach in most of the UK, working on instructions from the retail provider you pay rather than from you directly. For an overhead fault, an engineer can often diagnose the problem visually, replace a broken dropwire, restring a span, or in the case of a fallen pole arrange a replacement. Because the damage is in the open, the make-safe and the repair can frequently happen in a single visit, though a fallen pole that requires a new one to be set takes longer than a simple reconnection.
Underground repairs are more involved. The engineer must first locate the fault along a buried route, which can mean specialist test equipment, then gain access through a chamber or by excavation. Where digging is needed in a road or pavement, traffic management and permissions add time before any work begins. Water-damaged joints may need drying or replacing. For both types, you report the fault to your provider, which raises it with Openreach, and the same Ofcom compensation rules apply to a resulting loss of service regardless of whether the line is overhead or underground.
It helps to understand why an underground repair can stretch over days when an overhead one is resolved in an afternoon. Locating a buried fault to the metre, rather than the general span, often requires test gear that injects a signal and traces where it is lost, after which the team must confirm there are no other utilities in the way before opening the ground. Excavation in a public highway is itself regulated, with permits and traffic-management requirements that the engineer cannot simply bypass, so the calendar time includes waiting for permissions as well as the physical work. An overhead repair sidesteps almost all of this: the fault is visible, the make-safe can often be done from the road or a ladder, and a replacement dropwire or span is a faster job than a dig. For the household, the compensation position is the same either way, but the realistic timescale to restoration can differ sharply, which is useful to know when a provider quotes an estimated fix date.
Openreach's programme and the move to fibre
As the UK upgrades from copper to full fibre, a common assumption is that all new cable will be buried, but the reality is more practical. Openreach largely reuses the existing pole and duct network to carry fibre, threading new cable through ducts that already exist and running it along established pole routes. This keeps the rollout affordable and faster than digging new trenches everywhere. It also means that a property fed by an overhead dropwire today may well keep an overhead connection after the fibre upgrade, just with a different cable.
Openreach also opens its physical infrastructure to other providers. Under a regulated Physical Infrastructure Access product overseen by Ofcom, competing networks can use Openreach's poles and ducts to lay their own fibre, which encourages investment without every provider building duplicate poles and trenches. For households, the upshot is that the overhead and underground split is largely inherited rather than chosen, and the fibre upgrade tends to follow the existing route. Where new ducting is laid for a fresh development, underground is the norm, but retrofitting whole streets from overhead to underground is the exception rather than the rule.
What the digital switchover means for the line type
The migration from the legacy analogue network to digital phone services is sometimes confused with a physical rebuild of the street network, but the two are largely separate questions. Under Openreach's published programme to move services to all-IP, with the legacy PSTN withdrawn as the migration completes in 2027, the change for most households is in how the voice service is carried rather than in whether the cable to the property runs overhead or underground. A line that arrives on a pole today can carry a full-fibre digital service tomorrow using the same pole route, because the upgrade reuses the existing physical infrastructure wherever it can.
For a household, this means the overhead or underground question is mostly settled independently of the switchover. The more consequential change that comes with the digital service is power dependence: a digital phone relies on equipment inside the home that needs mains electricity, whereas the old copper line drew its power from the network. That shift matters far more to day-to-day resilience than whether the cable outside is strung between poles or buried in a duct, and it is the aspect of the upgrade most worth a household's attention regardless of which line type serves the address.
Frequently Asked Questions
Does it matter if my phone line is overhead or underground?
For day-to-day service the difference is usually invisible, but it affects which faults are most likely and how quickly they are fixed. Overhead lines are more exposed to wind and trees but quicker to repair, while underground cables are sheltered but slower to access when they fail. Both are maintained by Openreach and covered by the same compensation rules, so the line type does not change your entitlements.
Are underground phone lines more reliable?
Underground cables avoid wind, falling trees and most surface hazards, so they tend to suffer fewer weather-driven faults in normal conditions. Their weaknesses are flooding, ground movement and accidental strikes by others digging nearby, and faults take longer to reach and repair. Whether underground is more reliable in practice depends on the specific local hazards, such as flooding or frequent street works, rather than the technology alone.
How does Openreach repair an overhead line?
An engineer can usually diagnose an overhead fault on sight, then replace a broken dropwire, restring a span, or arrange a replacement for a fallen pole. Because the damage is in the open, the make-safe and repair often happen in one visit, though setting a new pole takes longer. You report the fault to your provider, which instructs Openreach to attend on the network side of the line.
Is Openreach burying more cables underground?
As it rolls out full fibre, Openreach largely reuses the existing pole and duct network rather than burying every new cable, because reusing infrastructure is faster and cheaper than trenching. New housing developments are typically built with underground ducting, but wholesale conversion of existing overhead streets to underground is uncommon. A home on an overhead dropwire today often keeps an overhead connection after the upgrade.
What happens if a bird or tree damages an overhead phone cable?
Damage from a falling branch, a fallen tree or contact with vegetation is a common cause of overhead faults, and it is reported to your retail provider, which raises the repair with Openreach. If a cable is brought down across a road or footpath it is a hazard and should be reported promptly and not touched. The make-safe usually comes first, followed by the permanent repair, which may be a separate later visit.
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