- Openreach builds and maintains the largest UK access network and sells wholesale access to retail providers on equal terms.
- Openreach is a legally separate company within BT Group, a structure overseen by Ofcom to support fair competition.
- Virgin Media operates its own separate cable network, while independent network builders, known as altnets, are expanding full fibre.
- Ofcom can impose extra obligations where a company holds significant market power (SMP), under the Communications Act 2003.
- The wholesale and retail layers are separate, so many retail providers can compete using the same underlying Openreach network.
The UK market splits into wholesale networks and retail providers. Openreach sells access to many ISPs on equal terms, Virgin Media runs its own network, altnets are growing, and Ofcom regulates competition.
Last reviewed: June 2026
Wholesale and retail layers
The UK broadband market is best understood as two layers. The wholesale layer is the physical network that carries the connection, while the retail layer is the providers that sell broadband packages to households. Many familiar broadband brands operate at the retail layer and buy access to the underlying network from a wholesale operator. This separation is what allows many providers to compete using the same physical infrastructure.
The largest wholesale access network is run by Openreach, which builds and maintains the lines, cabinets and fibre that reach most UK premises. Retail providers connect to the Openreach network and sell services over it, each adding their own pricing, customer service and extras.
Openreach and BT Group
Openreach is a legally separate company within BT Group. The separation, overseen by Ofcom, is designed to ensure that all retail providers, including BT's own retail arm, can buy wholesale access on equal terms. Openreach maintains the access network, carries out installations and repairs, and develops wholesale products such as FTTC, SOGEA and full fibre. It does not sell broadband directly to consumers; that is the role of the retail providers that use its network.
This model means that when a household orders broadband from many different brands, an Openreach engineer may carry out the work and the connection runs over Openreach infrastructure, even though the customer relationship is with the retail provider.
| Layer | Role | Examples |
|---|---|---|
| Wholesale access network | Builds and maintains physical lines and fibre | Openreach, Virgin Media network, altnets |
| Retail providers | Sell packages, billing and customer service | Many ISPs using underlying networks |
| Regulator | Sets competition and consumer rules | Ofcom under the Communications Act 2003 |
| Consumer | Chooses a retail provider over an available network | UK households and businesses |
Virgin Media and separate networks
Not all broadband runs over Openreach. Virgin Media operates its own separate network, built on hybrid fibre-coaxial technology, which reaches a substantial footprint of UK homes. Because it is a separate physical network, Virgin Media broadband is only available where that network has been built, and it competes directly with services delivered over Openreach. The existence of a second large network adds infrastructure competition in the areas it covers.
This is an important distinction. In much of the country, retail competition happens over a shared Openreach network, while in Virgin Media areas there is competition between separate networks as well as between retail providers.
The rise of altnets
A growing group of independent network builders, often called altnets, are constructing their own full fibre networks. These range from regional players to larger national builders. Altnets add genuine infrastructure competition by building new fibre rather than reselling existing access, and they have expanded full fibre availability, particularly in areas they have chosen to target. Some sell directly to consumers, while others provide wholesale access to retail partners.
The expansion of altnets, alongside Openreach and Virgin Media investment, is a major reason full fibre availability has grown quickly, as documented in Ofcom Connected Nations reporting. It also means that more addresses now have a genuine choice of underlying networks rather than a single option.
How Ofcom regulates competition
Ofcom regulates the market under powers in the Communications Act 2003. A central tool is the concept of significant market power. Where Ofcom finds that a company holds significant market power in a particular market, it can impose additional obligations, such as requirements to provide wholesale access, to do so on fair terms, and to meet transparency and quality conditions. These rules aim to prevent a dominant operator from using its position to disadvantage competitors.
Ofcom also sets the rules that protect consumers across all providers, including switching processes, complaint handling, automatic compensation and the codes of practice on advertised speeds. Together, the structural separation of Openreach and these market rules are designed to keep competition fair while encouraging investment in new networks.
What this means for households
For a household, the practical effect of this structure is choice. Most addresses can buy from several retail providers over the Openreach network, some can also choose Virgin Media or an altnet, and the rules that govern switching and complaints apply across providers. Knowing which networks serve an address, through an availability check, is the starting point for understanding the real options available.
How the wholesale model shapes prices and service
The split between wholesale and retail has a direct effect on what households pay and the service they receive. Because many retail providers buy access from the same wholesale network, they compete mainly on price, customer service, contract terms and extras rather than on the underlying line. This competition is part of what keeps consumer prices in check. At the same time, the wholesale charges that Openreach can levy are influenced by Ofcom where significant market power exists, which feeds through to retail pricing. The structure is designed to balance fair returns for network investment against affordable services for consumers.
Service quality is shaped by the same division. When a fault lies in the access network, it is Openreach or the relevant network operator that must fix it, while the retail provider manages the customer relationship and any compensation due. This is why a fault can sometimes involve both the provider and an engineer from the network operator, and why the provider remains the single point of contact for the customer even when the work is carried out by others.
Infrastructure competition and the rollout of fibre
The most significant recent change in the market is the surge of investment in full fibre. Openreach is building at scale, Virgin Media continues to upgrade its network, and altnets are laying new fibre across many areas. This infrastructure competition, where rival networks build rather than merely resell, is widely credited with accelerating the rollout that Ofcom Connected Nations reports document. For consumers it can mean genuine choice of underlying network at an address, which is a step beyond competition between retail brands on a single network.
Frequently Asked Questions
What is Openreach?
Openreach builds and maintains the largest UK access network, including lines, cabinets and fibre, and sells wholesale access to retail providers on equal terms. It does not sell broadband directly to consumers; retail providers use its network to do that.
Is BT the same as Openreach?
Openreach is a legally separate company within BT Group. The separation, overseen by Ofcom, is designed so that all retail providers, including BT's own retail arm, can buy wholesale access on equal terms. BT retail sells broadband to consumers, while Openreach runs the network and serves all providers equally. This is why an Openreach engineer may carry out work for many different broadband brands, not only BT.
What is an altnet?
An altnet is an independent network builder that constructs its own full fibre network rather than reselling existing access. Altnets add genuine infrastructure competition and have expanded full fibre availability, particularly in areas they have chosen to target. Some sell broadband directly to consumers, while others provide wholesale access to retail partners. Their growth, alongside Openreach and Virgin Media investment, is a major reason full fibre coverage has risen quickly in recent years.
How does Ofcom regulate broadband competition?
Ofcom regulates under the Communications Act 2003. Where a company holds significant market power, Ofcom can impose obligations such as providing wholesale access on fair terms and meeting transparency and quality conditions. It also sets consumer rules on switching, complaints and compensation.
What is significant market power?
Significant market power is a regulatory finding that a company is dominant in a particular market. Where Ofcom makes this finding, it can impose additional obligations on that company, such as providing wholesale access on fair terms and meeting transparency and quality conditions, to prevent it from using its position to disadvantage competitors and to keep the market open to other providers.
