Note: GCA published an updated draft specification in August 2026 ahead of the ITT. This article reflects those updates. All information remains subject to final confirmation in the ITT, due 21st August 2026.
If you supply technology to the emergency services sector, you’d be forgiven for not having followed NS4 particularly closely. It’s always been talked about as a telecoms and network framework — connectivity, WAN, voice services. Not obviously aimed at blue light suppliers.
But when GCA published the final lot structure earlier this year, something significant happened. Three entirely new lots appeared — Lots 9a, 9b and 9c — introduced specifically to support the emergency services sector through one of the biggest communications infrastructure transitions it’s ever faced.
These lots didn’t exist in NS3. They’ve never existed in any iteration of the Network Services framework before. And the application window opens on 21st August.
Why they were created
The UK’s emergency services are in the middle of replacing the Airwave network — the system that currently carries voice and data for police, fire and ambulance services — with the Emergency Services Network, built on commercial 4G and 5G infrastructure.
The Home Office’s Emergency Services Mobile Communications Programme (ESMCP) is managing this transition, and it creates significant, ongoing procurement demand. Public sector organisations need to buy devices, services and software that support both legacy Airwave operations and the new ESN — and they need a compliant route to do so.
The three Critical Communications lots are that route. GCA introduced them at the direct request of the Home Office ESMCP team, and they’re built specifically for the critical communications landscape. If your business operates in this space, NS4 is now one of the most relevant procurement frameworks in the public sector.
What the three Lots cover
Lot 9a is for devices — the hardware that supports critical communications. Handsets, mobile radios, satellite-enabled devices, SIM cards, cellular modules, data plans and antennas. If you manufacture, distribute or resell critical communications hardware that operates on Airwave, TETRA or ESN, this lot was built for you.
Lot 9b is for services — scoping, designing, building, running and maintaining critical communications technologies across ESN, Airwave, TETRA and commercial radio. It covers connectivity services including data plans and the full cellular and satellite technology stack. If you provide managed services, connectivity or implementation work for critical communications systems, this is where you sit.
Lot 9c is for software — the operations layer. Planning and network management software, cryptographic software, logging software. If you develop or resell software that supports the operation, management or security of critical communications networks, this is your lot.
Connectivity services including data plans are in scope for Lot 9b — but only where they’re specifically for Critical Communications Networks. GCA explicitly removed general commercial cellular connectivity from this lot in August 2026 to avoid conflicts with Lot 1. A general-purpose roaming SIM service is unlikely to fit here.
Who the buyers are
The buyer base for these lots spans the full blue light sector and beyond – police forces, PCCs, fire and rescue services, ambulance trusts, the Home Office and ESMCP programme team, Border Force, and NHS organisations with specialist communications requirements.
NS4 as a whole is used by over 180 public sector buying organisations. With the ESN transition driving significant re-procurement across the blue light sector over the next few years, the commercial opportunity here is genuinely substantial.
What you need to get in place
The ITT opens 21st August. Applications close 2nd October. That’s six weeks from window opening to deadline, and there are a few things worth getting in order now rather than after the ITT drops.
The most important is your Technical Ability Certificate, or TAC. Each lot requires a separate one — a reference contract demonstrating you’ve delivered the relevant services. You can’t reuse the same contract across multiple lots. It must also have started or been signed after 21st August 2023. GCA will validate it by contacting your customer directly, so give that contact a heads up now.
Beyond the TAC, get your compliance documentation in good shape. Cyber Essentials or Cyber Essentials Plus — the ITT will confirm the exact level, but CE Plus is the most likely requirement based on comparable GCA frameworks. You’ll also need a current and published Carbon Reduction Plan under PPN 015, insurance at the right levels, and financial accounts that meet the turnover thresholds.
And for the scored qualitative questions — the part that determines whether you get listed and at what position — assessors want concrete evidence. Named contracts, quantified outcomes, specific challenges solved. If you’ve been delivering critical communications technology to blue light services, that evidence is directly relevant and will carry real weight. Get it documented before the window opens.
One more lot worth knowing about
If your services involve connected devices, sensors or data connectivity in a public safety context — but don’t fall squarely within the critical communications definition — Lot 5 (IoT and Connected Places) may also be worth a look. GCA has acknowledged the qualification threshold for this lot is currently set very high and is actively seeking feedback before the ITT drops. If it applies to you, email networkservices@gca.gov.uk before 21st August.
The window is short
For suppliers who haven’t been tracking NS4 closely, the timeline is tighter than it looks. The preparation that matters — identifying your lots, confirming your TAC contracts qualify, getting your compliance documentation in order — needs to happen before the window opens, not after.
GCA have also made slides from their supplier surgery drop-in sessions available to download on the NS4 page at gca.gov.uk/agreements/RM6377 — worth reviewing before you apply.
If you’d like to talk through whether Lots 9a, 9b or 9c are right for your business and what a strong application looks like, our team can help.
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