O2 and Cellnex sign agreement to end Brighton Main Line ‘not-spots’ for 300,000 daily passengers

O2 joins landmark connectivity programme as Cellnex continues to deliver enhancements across one of the UK’s most vital commuter routes

LONDON, 15 June 2026  – Cellnex, the UK’s largest independent operator of telecommunications infrastructure, today announces that O2 has signed an agreement to join its Brighton Main Line (BML) connectivity project. The collaboration will see O2 access Cellnex UK’s purpose-built neutral host infrastructure, enabling the phased rollout of high-speed mobile connectivity, including 5G, to customers across the entire route over the coming months. This includes major commuter stations, London Victoria, London Bridge, and Clapham Junction. The news follows Cellnex signing Three UK in 2023, further demonstrating growing operator demand for the Brighton Main Line platform.

The Brighton Main Line is one of the UK’s highest-density rail routes: a 108 km corridor linking London, Gatwick Airport and the South Coast with Thameslink, Southern, Gatwick Express, Great Western Railway and London Overground Services. It serves more than 300,000 passengers every weekday, of which 50,000 are travellers to and from the second busiest airport in the UK, and accommodates 1,700 daily train movements.

State of the art indoor coverage solutions are being deployed to significantly enhance mobile phone connection in three of the most important London stations, London Victoria, London Bridge, and Clapham Junction, which account for roughly 19% of railway passenger traffic to and from the capital from outside London.

Developed in partnership with Network Rail under a 25-year contract awarded in 2021, Cellnex’s infrastructure represents a major engineering achievement, bringing seamless connectivity to a route long challenged by deep cuttings, long tunnels and Victorian-era station infrastructure. Once fully activated, the shared infrastructure will deliver high speed connectivity across 99% of the 108 km route, drastically reducing historical not-spots and ensuring passengers enjoy reliable calls, uninterrupted streaming and stable app performance throughout their journey.

Steve Cray, Managing Director of Cellnex UK, said: 

“Regular railway passengers will understand the frustration of losing signal mid-conversation or spending whole journeys with buffering videos. With O2 now on board, many more passengers are going to notice the difference on one of the UK’s most important commuter routes. This collaboration stands as one of the most significant end-to-end telecommunications infrastructure deployments in British railway so far, and we are proud to be setting a new standard for the UK’s entire rail network.”

As a neutral host provider, Cellnex designed, planned, and built this infrastructure, enabling all UK mobile network operators (MNOs) to access shared connectivity, reducing capital investment, lowering cost per megabyte and minimising environmental impact. With the infrastructure now in place, Cellnex is actively working to expand MNO participation, with the ambition that every passenger, regardless of their network, can benefit from enhanced connectivity along the Brighton Main Line.

For O2 customers who regularly travel on the Brighton Main Line, the agreement marks the start of a phased rollout that will deliver more reliable connectivity over the coming months, with coverage improvements being brought live in stages across the route.

Professor Robert Joyce, Director of Mobile Access Engineering at O2, said:

“Our £700m Mobile Transformation Plan is focused on delivering reliable connectivity in the moments that matter most, and railway lines are a key part of that. By working with Cellnex to improve connectivity along the Brighton Main Line, we’ll be bringing improved coverage and capacity to customers travelling from the coast to the capital over the coming months.”

Paul Richmond, Head of Business Development for Network Rail, said:

“Passengers on the Brighton Main Line deserve connectivity that matches the importance of this route, and our long-term partnership with Cellnex is transforming what has historically been one of the most technically demanding corridors for mobile coverage into a showcase for modern railway connectivity. A huge amount of collaboration has gone into this project over the last few years to support the infrastructure for this project on a railway that is constantly operational.

“With O2 now on board, even more passengers will soon experience the benefits of this investment every time they travel.”

The three-year build programme has seen more than 129,000 working hours delivered across 11,000+ worker entries on the line side and at stations. The infrastructure deployed by Cellnex includes 130 km of high-capacity fibre, four Base Station Hotels to host MNO equipment, 39 Distributed Antenna Systems (DAS) within tunnels and along trackside locations, a dedicated station DAS at London Bridge, London Victoria and Clapham Junction, and 16 macro sites along the railway route.

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About Cellnex UK

Cellnex is Europe’s largest telecommunications towers and infrastructure operator, enabling operators to access a wide network of telecommunications infrastructure on a shared-use basis, and thus helping to reduce access barriers and to improve services in the most remote areas, whilst also contributing to more sustainable deployment. The Company manages a portfolio of more than 110,000 sites, including forecast rollouts up to 2030, in 10 European countries, with a significant footprint in Spain, France, the United Kingdom, Italy and Poland. Cellnex, which is listed on the Spanish Stock Exchange, is part of the selective IBEX35 and Euro Stoxx 100 and enjoys outstanding positions on the main sustainability indexes such as FTSE4Good, MSCI and DJSI Europe.

For further information, please visit: Cellnex Telecom

About Network Rail

We own, operate and develop Britain’s railway infrastructure; that’s 20,000 miles of track, 30,000 bridges, tunnels and viaducts and the thousands of signals, level crossings and stations. We run 20 of the UK’s largest stations while all the others, over 2,500, are run by the country’s train operating companies.

Usually, there are almost five million journeys made in the UK and over 600 freight trains run on the network. People depend on Britain’s railway for their daily commute, to visit friends and loved ones and to get them home safe every day. Our role is to deliver a safe and reliable railway, so we carefully manage and deliver thousands of projects every year that form part of the multi-billion pound Railway Upgrade Plan, to grow and expand the nation’s railway network to respond to the tremendous growth and demand the railway has experienced – a doubling of passenger journeys over the past 20 years.

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Notes to Editor

Percentage of London stations passenger travel calculated by using ORR estimates for station usage Apr 2024 to Mar 2025 (Estimates of station usage | ORR Data Portal).

Major London commuter stations considered as the 13 busiest terminating stations with services arriving from outside the Greater London area:

• London Liverpool Street
• London Waterloo
• London Paddington
• London Bridge
• London Victoria
• Stratford
• London Euston
• London St Pancras Int’l
• London King’s Cross
• East Croydon
• London Charing Cross

Total entries/exits/interchanges: 699,096,448 – of which at Victoria, London Bridge and Clapham Junction: 132,917,545 – 19% of total.