Building the Platform | Part 1 How to Write a Brief That a Platform Can Actually Answer

The brief is where platform thinking either takes off or gets derailed.

Most procurement briefs for SEND capital projects in the UK are built around a single question: what kind of building do we need? They focus on specifics like square footage, number of classrooms, site address, and completion date. These are output specs, which describe a thing. And for a long time, output specs were the right tool for the job - because every project was a separate thing. But that's not the situation now.

Local authorities, multi-academy trusts, and DfE programme managers are facing a different reality. The Schools White Paper has committed £3.7 billion to create 60,000 new specialist places. Inclusion bases are expected in every secondary school. The demand is not just a one-time thing, it's sustained and timetabled. Under those conditions, a brief that describes a building is not just insufficient, it's also counterproductive. Because it doesn't allow the market to offer what it needs to: a repeatable delivery capability.

What an Output Brief Actually Signals to the Market

When a procurement team issues a brief for a specific building on a specific site, it sends a message to the supply chain: treat this as a one-off. Manufacturers read that signal and price accordingly - they absorb design costs, tooling costs, and mobilisation costs into a single contract with no guarantee of follow-on work. Supply chains don't invest in the capacity, systems, or people that portfolio-level delivery requires, because the demand signal doesn't justify it. And then the procurement body wonders why modular construction costs more than expected, or why the programme takes longer than the technology should allow. The answer is in the brief they issued.

The Procurement Act 2023, which came into force in February 2025, gives contracting authorities more discretion about how they design and evaluate procurements. That discretion is an invitation, but most procurement teams haven't accepted it yet. So, what's the distinction that changes everything?

A portfolio-framed brief doesn't ask what building do we need, it asks: what delivery capability do we need to create, and over what programme? That's not just semantics, it's a different commercial signal to the market, and it produces different responses.

Where an output brief produces tenders for a building, an outcome brief produces proposals for a platform - a stable, repeatable system capable of delivering multiple facilities across a defined programme, with costs that reduce and quality that improves as the platform matures. The difference shows up in four specific places within the brief itself.

1. Programme horizon

An output brief specifies a single completion date. An outcome brief specifies a programme horizon - typically three to five years - within which multiple facilities will be required. This change transforms the supply chain's investment calculus. Manufacturers can commit to tooling, installers can commit to trained teams, and design effort can be amortised rather than repeated.

2. Performance requirements versus product requirements

An output brief specifies products: room sizes, material specs, structural systems. An outcome brief specifies performance: acoustic standards, sensory environment criteria, thermal comfort thresholds, adaptability over time. Performance requirements allow the platform to evolve and improve. Product requirements lock it in place.

3. Evaluation criteria

Output briefs are typically evaluated on price and programme. Outcome briefs should weight platform maturity - evidence that the supplier has a proven, repeatable system - alongside the specific project response. Cost-led procurement on frameworks with similar capital projects provides the opportunity to continually improve on unit costs, working collaboratively with the supply chain. That collaborative improvement only happens if the evaluation criteria ask for it.

4. Supply chain continuity provisions

An output brief is silent on what happens next. An outcome brief includes provisions for how the supply chain relationship will be maintained, developed, and governed across the programme. It treats the supplier relationship as infrastructure, not a transaction.

Why This Feels Difficult - and Why That Feeling Is Misleading

Procurement teams often resist outcome-based briefs for two reasons that sound practical but are, in most cases, inherited assumptions rather than genuine constraints.

The first is accountability. Output specs feel safer because they're auditable. If the brief says 450 square metres and the building delivers 450 square metres, the procurement was successful. Outcome specs require judgement - about whether the delivery capability is genuinely mature, whether the platform performs as specified, whether the supply chain relationship is structured for the long term. That judgement feels exposed. But the accountability argument has quietly reversed. In a policy environment where 60,000 specialist places are expected and delivery timelines are visible, failing to build a capable delivery system is the accountability risk. A series of one-off projects that deliver inconsistently, slowly, and at rising cost is not a defensible position. A well-governed platform programme, even if imperfect in its early phases, is.

The second resistance is legal. Procurement teams worry that outcome-based briefs are harder to defend in the event of a challenge. In practice, the new flexibilities within the Procurement Act 2023 are designed to support more sophisticated, relationship-based procurement approaches. The legal landscape has moved, but procurement practice, in most authorities, has not yet followed. So, what's the conversation that needs to happen first? Before a portfolio-framed brief can be written, a conversation needs to happen that most capital programmes do not currently structure. It's not a conversation about buildings. It's a conversation about estate strategy - demand forecasting across a three to five year horizon, site pipeline, programme interdependencies, and the governance model that will oversee delivery across multiple facilities. Without that conversation, even the best-intentioned outcome brief will default back to project logic, because the client organisation has not yet formed a view of what it is actually trying to build at system level.

Building the Platform is a series for procurement leads in local authorities, multi-academy trusts, and DfE programme teams.

Part 2 examines why your supply chain cannot currently scale - and where the responsibility for that sits.

TSL Consult provides modular construction strategy and procurement advisory for education estates.