Network sharing and co-location arrangements take several forms: bilateral sharing between mobile operators, tower company (towerco) models where passive infrastructure is owned and managed by a third party, and shared infrastructure arrangements for fibre and fixed-wireless networks. The agreements cover site access, cost sharing, governance, capacity allocation, service levels and the operational interface between independent networks. Active sharing (RAN sharing) is commercially and technically different from passive sharing (mast and site co-location), and the contractual framework must reflect this. Competition law adds a regulatory dimension: the CMA and Ofcom are concerned to ensure that sharing arrangements are not anti-competitive, and a separate access duty arises under the Communications (Access to Infrastructure) Regulations 2016. Getting the commercial structure right from the outset reduces the risk of regulatory challenge during implementation.

Why network sharing agreements need specialist attention

The CMA and Ofcom assess network sharing arrangements to ensure they are not anti-competitive. Under the Competition Act 1998, a sharing arrangement may be investigated under the Chapter I prohibition (agreements restricting competition) or the Chapter II prohibition (abuse of dominance). Section 371 of the Communications Act 2003 makes those functions concurrent functions of Ofcom and the CMA for activities connected with communications matters, so for an arrangement between network providers the investigating regulator is as likely to be Ofcom as the CMA. The concern is that sharing may reduce independent network competition or facilitate coordination between operators.

Code Powers under the Electronic Communications Code (Schedule 3A Communications Act 2003) govern rights to install and maintain apparatus on land, including shared sites. Paragraph 74 of the Code, as amended by the Product Security and Telecommunications Infrastructure Act 2022 with effect from 7 February 2023, allows one operator to install and keep lines passing over adjacent land from another operator’s apparatus, and to upgrade that apparatus, with the main operator’s agreement. It confers no general duty to share. A separate right of access to physical infrastructure on fair and reasonable terms arises under regulation 6 of the Communications (Access to Infrastructure) Regulations 2016 for a network provider deploying elements of a high-speed electronic communications network, and the infrastructure operator may refuse on objective, transparent and proportionate grounds. Tower companies holding Code Powers hold the same rights, and are subject to the same access obligations, as other operators.

Active infrastructure sharing (RAN sharing) raises different issues from passive sharing (mast/site sharing). RAN sharing involves shared radio access networks and capacity purchasing. The CMA and Ofcom scrutinise active sharing more closely because the operators are no longer independent on the radio access layer, which may reduce competitive differentiation on coverage and capacity.

What a sharing agreement has to settle

A sharing agreement has to settle four things before the commercial terms are fixed. The competition analysis comes first, because it constrains what can be agreed on pricing, coverage and capacity. Regulatory risk is then allocated between the parties, including the cost of meeting a regulation 6 access request from a third party. Passive and active sharing are documented separately, because the regulatory treatment differs. And in a towerco transaction the terms address how Code Powers pass with the sites, and how the towerco meets access requests once it holds them.

Spectrum sharing adds a further category. A transfer of rights under a wireless telegraphy licence is void unless made in accordance with regulations under section 30 of the Wireless Telegraphy Act 2006, and the Wireless Telegraphy (Mobile Spectrum Trading) Regulations 2011 authorise a concurrent transfer, under which the transferred rights and obligations become the transferee’s while continuing to bind the transferor. The obligations run to both parties, and the commercial terms have to allocate the cost of meeting them.

Data protection complexity arises where operators share core network infrastructure and both process personal data from calls and data services. Each operator may be a separate controller or joint controller. The data sharing agreement must clarify UK GDPR responsibilities.

Common issue	Better approach
Competition law implications not assessed pre-negotiation	CMA risk assessment completed before terms are agreed
Passive and active sharing frameworks conflated	Clear distinction between infrastructure sharing and RAN/core sharing
Cost of third-party access left undefined	Documented cost basis for access under regulation 6 of the 2016 Regulations
Towerco transition obligations unaddressed	Code Powers transfer and ongoing access obligations specified
Controller/processor roles unclear	UK GDPR Article 26 joint controller analysis completed

The regulatory treatment of network sharing differs depending on whether the arrangement is passive or active. Passive sharing involves infrastructure elements only: masts, towers, ducts, power supply and physical site access. This is the least complex form of sharing because neither party accesses the other’s radio network or customer traffic. Active sharing involves radio access network elements: spectrum, antennas, baseband units and potentially core network functions. Active sharing is more likely to engage competition law concerns because it can reduce the degree of independent infrastructure competition between the sharing parties.

Network sharing is not anti-competitive per se. Sharing arrangements can deliver consumer benefits through faster rollout, reduced costs and improved coverage, particularly in rural areas, and neither regulator treats sharing as objectionable in itself. The competition law question is whether the specific arrangement restricts independent decision-making to an extent that harms consumers. The relevant framework is Chapter I of the Competition Act 1998, which prohibits agreements that prevent, restrict or distort competition. Sharing agreements that include provisions on pricing, coverage commitments or capacity allocation require careful structuring to ensure they fall within a permissible efficiency-enhancing framework. In its final report of 5 December 2024 on the Vodafone and Three joint venture, the CMA found a substantial lessening of competition in retail and wholesale mobile but cleared the transaction on binding network investment commitments. Those commitments were carried into both undertakings under section 82 of the Enterprise Act 2002, accepted on 28 March 2025, and a variation of the merged entity’s spectrum licence under Schedule 1 to the Wireless Telegraphy Act 2006, accepted by Ofcom on 3 April 2025. The merger completed on 31 May 2025. The structure is worth knowing: a merger remedy landed in a spectrum licence condition, with Ofcom holding primary monitoring responsibility.

Towerco agreements add a further dimension. Code Powers are conferred by Ofcom, by a direction under section 106 of the Communications Act 2003, and an independent tower company holding a direction stands on the same footing as a mobile network operator. Holding Code Powers does not by itself give rights over any particular site: the operator acquires code rights under Schedule 3A of the Communications Act 2003 either by agreement with the occupier or, where the occupier will not agree, by an order under paragraph 20 imposing an agreement. That route runs through a paragraph 20(2) notice, which since 7 November 2023 must set out the alternative dispute resolution options and the consequences of refusing them, a 28 day period under paragraph 20(3), and an obligation on the operator to consider alternative dispute resolution before applying. An application is made to the county court, the First-tier Tribunal (Property Chamber) or the Upper Tribunal (Lands Chamber). The commercial terms of a towerco agreement are negotiated against that fallback.

How we structure the agreement

We structure network sharing and co-location arrangements by starting with the competition analysis and distinguishing passive from active sharing. For passive sharing, including towerco models, we document the cost basis on which access is offered under regulation 6 of the Communications (Access to Infrastructure) Regulations 2016 and advise on the obligations that transfer with the infrastructure. For active sharing, we advise on regulator engagement and the conditions likely to be sought. We draft governance provisions allocating decision-making authority and regulatory risk between the parties. We address the data protection consequences of shared processing with a clear controller allocation.

How Bratby Law helps

• Competition law risk assessment: analysing whether the proposed sharing arrangement raises concerns under the Competition Act 1998 Chapter I or Chapter II prohibitions, advising on self-assessment against those prohibitions, and structuring the arrangement to minimise competition risk
• Sharing agreement drafting and negotiation: structuring and drafting the commercial framework for passive or active sharing, including site access terms, cost allocation methodology, capacity purchase arrangements, governance provisions and the operational interface between the parties’ networks
• Code Powers and infrastructure sharing: advising on Code Powers under the Electronic Communications Code and the access to physical infrastructure regime under the Communications (Access to Infrastructure) Regulations 2016, including the terms on which access is offered and the transition of Code Powers in towerco transactions
• Spectrum sharing and licence analysis: advising on the regulatory implications of spectrum sharing arrangements, including Ofcom’s position on shared spectrum licences, spectrum cap assessment and the interaction between sharing and licence conditions
• Data protection for shared networks: structuring the data protection arrangements for shared core infrastructure, including controller/processor classification, UK GDPR Article 26 joint controller arrangements, subject access request handling and breach notification protocols
• Governance and dispute resolution: drafting governance frameworks for the shared operation, including decision-making authority, escalation mechanisms, technical working groups and dispute resolution provisions that reflect the regulatory context
• Tower company and shared infrastructure transactions: advising on the structuring of towerco transactions, including the transfer of sites from operators to tower companies, transition of Code Powers, ongoing infrastructure access obligations, anchor tenancy terms and the commercial framework for third-party co-location

Rob Bratby advises mobile operators, tower companies and infrastructure investors on network sharing and co-location arrangements, bringing experience from a one-year secondment to Oftel and from General Counsel roles at telecoms operators.

Frequently asked questions

How long does a network sharing agreement typically take to negotiate?

Six to twelve months from heads of terms to execution is typical for an active sharing arrangement. The timeline depends on whether the arrangement is passive or active sharing, whether CMA engagement is required, and the complexity of the governance and cost-sharing provisions. Active RAN sharing takes longer because the technical and competition issues are more complex. Parallel workstreams (commercial terms, competition analysis, technical design, data protection) reduce the overall timeline if properly managed.

Do we need CMA approval for network sharing?

There is no approval or notification route under the Competition Act 1998. The notification regime in sections 12 to 16 and 20 to 24 of that Act ceased to have effect on 1 May 2004, so the parties self-assess against the Chapter I and Chapter II prohibitions. A sharing joint venture may amount to a relevant merger situation, in which case the parties may choose to notify the CMA under the Enterprise Act 2002, and the CMA may open an investigation of its own initiative whether or not they do.

What sharing obligations apply to physical infrastructure?

The Electronic Communications Code confers no general duty to share physical infrastructure. The duty arises under regulation 6 of the Communications (Access to Infrastructure) Regulations 2016: an infrastructure operator that receives a written request from a network provider, made with a view to deploying elements of a high-speed electronic communications network using that infrastructure, must within two months agree to provide access on fair and reasonable terms. It may refuse only where it considers the request unreasonable on objective, transparent and proportionate grounds, and regulation 6(3) gives examples including the technical suitability of the infrastructure, the space available taking account of the operator’s own demonstrated future needs, safety, network security and the availability of a viable alternative form of wholesale access on fair and reasonable terms.

What is the difference between passive and active sharing?

Passive sharing covers infrastructure not directly involved in data transmission (masts, ducts, co-location sites). Active sharing covers infrastructure directly involved in transmission (RANs, core network elements). Active sharing is more heavily scrutinised because of closer operational integration and competition concerns.

What data protection issues arise from network sharing?

Where operators share core infrastructure and both process personal data, each is typically a controller in its own right, although the allocation is fact-sensitive and turns on who determines the purposes and essential means of each processing operation. The data sharing agreement must clarify UK GDPR responsibilities including subject access requests, breach notification and DPIAs. Joint controllers must settle their respective responsibilities in an arrangement under Article 26 UK GDPR.

Can we exclude third-party operators from our shared site?

Holding Code Powers does not of itself oblige you to admit another operator to your site. A request for access to physical infrastructure under regulation 6 of the Communications (Access to Infrastructure) Regulations 2016, made with a view to deploying elements of a high-speed electronic communications network, must be met on fair and reasonable terms unless you consider it unreasonable on objective, transparent and proportionate grounds, which regulation 6(3) illustrates by reference to technical suitability, available space measured against your own demonstrated future needs, safety, security and the availability of a viable alternative form of wholesale access. A refusal may separately raise questions under the Chapter I and Chapter II prohibitions, depending on the parties’ market positions.

What governance structure works best for a network sharing JV?

Most active sharing arrangements use a JV company or partnership with a board comprising representatives of each operator. Key decisions (capacity allocation changes, new site deployments, technology upgrades, third-party access) are reserved matters requiring unanimous consent. Day-to-day operations are delegated to a management team with authority to act within agreed parameters. The governance framework must address what happens when the operators disagree on a reserved matter, which is why deadlock resolution provisions are critical. For passive sharing, a simpler contractual governance structure typically suffices, with a joint technical committee managing access and capacity allocation.

Related transactions pages

See also our other transactions pages:

• Mergers and Acquisitions (M&A)
• Private equity
• SaaS and Cloud Services
• Subsea cables
• MVNOs and MVNEs
• Interconnection, peering and access agreements
• Digital Infrastructure Projects
• Data Commercialisation and Licensing
• NSIA Clearances

Independent directory rankings

Our specialist expertise is recognised in major independent legal directories:

• Chambers & Partners: Rob Bratby is ranked as a Band 2 lawyer in the UK Guide 2026 in the “Telecommunications” category: Chambers
• The Legal 500: Rob Bratby is listed as a Leading Partner for Telecoms in London (TMT: IT and Telecoms). The Legal 500
• Lexology: Rob Bratby is recognised in the Lexology Index as a Global Elite Thought Leader for telecoms and media, and as a Thought Leader for data privacy and protection: Lexology