In short: The UK's industrial renaissance — gigafactories, semicon plants, advanced pharma, food and drink reshoring — is happening on greenfield sites. The brownfield retrofit decisions about WiFi-vs-5G that dominate the conversation in legacy plants don't apply here. New-build operators get to design the factory from the wireless layer outwards, and many are designing private 5G in before the foundations are poured.
Key Takeaways
- Cable trays are the costliest part of a brownfield retrofit — and the biggest argument against any change of layout. New builds can skip them where wireless is good enough, saving capex and unlocking flexible floor plans
- Robotics and AI inspection are bandwidth-hungry by default — designing for 10,000+ sensors and dozens of mobile robots means the wireless layer is the choice, not an afterthought
- Vertical takeoff beats horizontal retrofit — a greenfield plant with private 5G from day one can validate Industry 4.0 use cases faster than a brownfield site spending the first year tearing out copper
In a nutshell
A new wave of UK factories
For the first time in a generation, the UK is building serious new manufacturing capacity. AESC and the Tata-backed Agratas gigafactories. Pragmatic Semiconductor's Sedgefield FlexLogIC fab. Several food-and-drink mega-sites driven by the squeeze on imports. Pharma capacity at Catapult sites and contract manufacturers. Defence and aerospace expansions at BAE, Rolls-Royce, Airbus UK. The £4.5bn Advanced Manufacturing Plan and the recent green-industries investment commitments have shifted the picture quickly.
These aren't brownfield refits. They're greenfield projects on sites where the operator gets to specify the production line, the building services, the IT infrastructure and — critically — the wireless layer from a blank slate. The decisions made in the design phase will outlive the first wave of robots and shape what the plant can do for thirty years.
The cable-tray tax on flexibility
If you've worked on a brownfield manufacturing IT project you've encountered the cable-tray tax. Every change to the production line — moving a cell, adding a robot, repurposing a building — requires physical re-cabling. Conduit gets pulled. Cable trays get extended. Switches get added. The plant manager who wants to reconfigure for a new product can spend six figures and three months on the infrastructure before the line moves at all.
The reason this gets accepted is that, historically, wired Ethernet was the only sensible way to carry production data with the determinism manufacturing needed. WiFi was good enough for office laptops, not for safety PLCs. So plants standardised on copper, and copper standardised on a layout.
Private 5G changes the economics. Industrial 5G NR delivers deterministic, sub-10ms latency, redundant connectivity for the kinds of safety and process control that previously needed cable. The IEC TSN (Time-Sensitive Networking) extensions and 3GPP Release 16/17 URLLC features close the gap on the hardest use cases. And the licensing is increasingly straightforward — Ofcom's Shared Access framework was designed for exactly this kind of industrial deployment.
For a new build, that means cable trays only where they're truly needed (high-voltage power, dense fixed sensor banks at the line, building services). Everything else — robotics, mobile carts, AI inspection cameras, AR headsets, handhelds, environmental sensors, security cameras — can be wireless. Capex falls. Build time shortens. And the line is flexible from the day it opens.
Robotics and AI: the bandwidth is the baseline
Modern manufacturing isn't a single problem; it's a stack of bandwidth-hungry use cases that compound:
- Mobile robotics: AMRs and AGVs transporting materials between cells. Each robot streams sensor data, accepts navigation updates, and coordinates with other robots in real time. A modest fleet of 20 AMRs can produce a Gbps of aggregated traffic.
- AI inspection: High-resolution cameras on the production line stream 4K or higher video to edge AI servers for real-time defect detection. A single line can have a dozen camera positions, each generating hundreds of megabits per second.
- Predictive maintenance: Vibration, thermal, acoustic and current-draw sensors on every motor, every bearing, every pump. A modern factory floor easily runs 10,000-50,000 such sensors, each updating frequently.
- AR-assisted maintenance and training: Technicians wearing AR headsets receive live overlays, step-by-step instructions, and remote expert support. Each headset wants ~100 Mbps with low latency.
- Digital twin: Continuous data feeds from every PLC, every sensor, every robot aggregated into a real-time digital model of the plant. The digital twin is only as fresh as the network feeding it.
In a brownfield retrofit, these arrive incrementally and each one fights the existing infrastructure. In a greenfield build, the architect can spec the wireless layer to handle the whole stack from day one — and then load it progressively as the production lines come online.
Vertical takeoff: from groundbreaking to first product
The strategic argument for wireless-first design is time. A greenfield factory is in a race: from groundbreaking to first product, every month of delay is millions in deferred revenue and unrecouped capex. Anything that compresses that timeline matters.
A wireless-first factory compresses the build in several ways at once. Fewer cable trays mean faster construction and fewer trade dependencies. A common wireless layer means commissioning happens against a single network rather than a dozen vendor-specific WiFi islands. Robotics and inspection systems can be validated in their final layout from the moment the building is dry, rather than after the cabling subcontractor finishes. And changes during the commissioning phase — which are inevitable — don't require re-pulling cable.
The contrasting picture is the brownfield site spending the first year of an Industry 4.0 project tearing out copper to make room for the new architecture. By the time they're ready to validate the first robotic cell, the greenfield site has been running production for six months.
What greenfield operators are actually doing
In conversations with UK reshoring projects we've worked with, three patterns recur:
Pattern one: 5G as the data backbone, WiFi as the guest layer. The site runs a managed private 5G network as the primary connectivity for everything operational — production, robotics, building services, security. WiFi 6E is provided for office space and visitor access, on a separate VLAN with no path to operational systems. This pattern is winning at sites where the operational scale justifies the network investment.
Pattern two: 5G first, wired only where physics requires. The plant designer starts from the assumption that everything is wireless, then identifies the small set of use cases (very-high-resolution machine vision, certain safety-rated motion-control loops, high-current power) where wired is genuinely necessary. The result is dramatically reduced cable infrastructure.
Pattern three: 5G as the future-proof layer over a smaller-than-default copper backbone. The plant runs a conventional industrial Ethernet for today's fixed equipment, with private 5G layered on for mobile assets, sensors, AI inspection and future expansion. This pattern suits operators who want a familiar core today but a clear migration path.
What all three share is the recognition that wireless isn't a retrofit — it's a design decision. And the operators making it now will spend the next thirty years compounding the advantage.
The boring infrastructure decision under the gigafactory
Gigafactory openings make the news. Wireless infrastructure decisions don't. But the UK's industrial renaissance is being shaped by a series of unglamorous architectural choices made eighteen months before any product is shipped. Building wireless-first is one of them — and it's the one that quietly determines whether the plant can flex with the market, scale with the product, and adopt the next decade of Industry 4.0 without going back to the cabling drawing.
For UK reshoring operators, that's not a luxury. It's the design choice that justifies the rest of the capex.