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. Each requires industry experience to structure, negotiate and document. 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 Code Powers under the Electronic Communications Code impose infrastructure access obligations. 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, the CMA can investigate whether a sharing arrangement infringes the Chapter I prohibition (agreements restricting competition) or Chapter II prohibition (abuse of dominance). 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. Part 5A of the Code (paragraphs 74 onwards, inserted by the Product Security and Telecommunications Infrastructure Act 2022) imposes obligations on operators with Code Powers to share physical infrastructure on fair and reasonable terms. These obligations apply regardless of any commercial sharing arrangement between parties. Tower companies holding Code Powers are subject to the same infrastructure sharing obligations.

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.

Where clients get it wrong

Network sharing deals fail in three directions. First, parties agree commercial terms without understanding the competition law overlay and discover during CMA review that the arrangement triggers third-party access obligations. Second, parties do not allocate regulatory risk, creating disputes about who bears the cost of Code Powers infrastructure sharing obligations. Third, parties conflate passive and active sharing and apply the wrong regulatory template. A fourth category arises in towerco transactions, where operators transferring sites to a tower company do not adequately address the transition of Code Powers and the ongoing infrastructure access obligations that attach to the towerco as the new Code operator.

Spectrum sharing adds a further category. Ofcom issues spectrum licences to individual operators and is cautious about arrangements where two operators share a single licence. Shared spectrum creates uncertainty about who controls the spectrum and who bears the cost of licence condition compliance.

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
Code Powers cost allocation left undefined	Documented cost bases for third-party Code Powers access
Towerco transition obligations unaddressed	Code Powers transfer and ongoing access obligations specified
Controller/processor roles unclear	UK GDPR Article 26 joint controller analysis completed

What good looks like

Bratby Law structures network sharing and co-location arrangements by starting with competition law risk assessment and distinguishing passive from active sharing. For passive sharing (including towerco models), we document the cost basis for third-party access under the Code Powers infrastructure sharing provisions and advise on the regulatory obligations that transfer with the infrastructure. For active sharing, we advise on CMA engagement and the likely conditions the CMA will impose. We draft governance provisions allocating decision-making authority and regulatory risk between parties. We address data protection obligations from shared processing with clear controller/processor allocations.

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 CMA notification strategy and likely conditions, 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 Part 5A obligations (paragraphs 74 onwards) to share physical infrastructure on fair and reasonable terms, including the cost methodology for third-party access pricing 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 agreements, 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 Oftel, Ofcom and General Counsel roles at telecoms operators. Bratby Law is ranked in Chambers UK (Band 2) for telecoms and recognised as a Legal 500 Leading Partner.

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 a significant 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?

The CMA has no formal approval requirement. However, if the arrangement raises competition concerns, you can notify under the Competition Act 1998 and request guidance. Most RAN sharing arrangements are notified because of material competition implications.

What do the Code Powers infrastructure sharing provisions require?

Part 5A of the Electronic Communications Code (paragraphs 74 onwards of Schedule 3A) requires operators holding Code Powers to share physical infrastructure on fair and reasonable terms where it is technically feasible to do so. The terms must reflect the costs of providing access. These provisions were inserted by the Product Security and Telecommunications Infrastructure Act 2022 and apply to all operators with Code Powers, including tower companies.

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 a controller. The data sharing agreement must clarify UK GDPR responsibilities including subject access requests, breach notification and DPIAs. Joint controller arrangements require an Article 26 UK GDPR agreement.

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

Not if you hold Code Powers. Part 5A of the Electronic Communications Code requires operators with Code Powers to share physical infrastructure on fair and reasonable terms where technically feasible. You can impose reasonable technical requirements for access, but you cannot refuse access on purely commercial grounds.

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.

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• Interconnection, Peering and Access Agreements
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• 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 – Telecoms” in London (TMT – IT & Telecoms): The Legal 500
• Lexology: Rob Bratby is featured on Lexology’s expert profiles as a Global Elite Thought Leader for data: Lexology