Making Better Choices for Britain's Infrastructure.

The Golden Thread: Defending Procurement Decisions Under the Procurement Act 2023

For decades, the way we’ve chosen contractors for big public projects, new railways, tunnels, and hospitals, hasn't always served us well. We’ve seen projects run over budget, finish late, and a tragic realisation that sometimes, the focus on the lowest price has come at the expense of safety and quality. The public rightly expects better. Now, a trio of new laws has completely rewritten the rulebook, demanding a new approach.

The government has responded with the Procurement Act, the Economic Crime Act, and the Building Safety Act. Together, they send a clear message: when we spend public money, we must demand real value, total transparency, and the highest standards of safety and integrity. Simply picking the cheapest offer is no longer an option. We now have a legal duty to choose the 'Most Advantageous' bid, which means weighing up everything from long-term running costs and environmental benefits to the skills and competence of the team.

This is a huge step forward, but it also presents a challenge. How do you fairly compare two multi-billion-pound bids when one offers a lower price, but the other promises to create more local jobs and uses a more innovative, safer construction technique? Old-fashioned scoring systems often struggle with this, relying on arbitrary numbers that can hide the real reason for a decision.

The Procurement Act 2023 (PA23) represents the most significant overhaul of UK public procurement in a generation. It moves us away from the familiar "Most Economically Advantageous Tender" (MEAT) and towards the more flexible, and potentially more challenging, "Most Advantageous Tender" (MAT).

This new flexibility, however, comes with a critical sting in the tail: an unprecedented requirement for transparency, captured in a new "causal chain" of documentation. This chain, stretching from the initial methodology to the final assessment summary, is only as strong as its weakest link. For a contracting authority, a weak link is not just a procedural error; it is a direct invitation for a legal challenge.

The challenge for authorities is to find an evaluation model that is not only flexible enough to identify the MAT but also robust and transparent enough to survive the intense scrutiny PA23 guarantees. The solution may lie in an approach that marries the principles of US Federal Acquisition methodologies (US FAM) with a transparent Cost-Benefit Analysis (CBA). This hybrid model provides the "golden thread" of logic needed to build a defensible and robust procurement.

The PA23's New Causal Chain: A Legal Tightrope

To understand why a new methodology is essential, we must first appreciate the legal tightrope created by the Act. The process establishes a direct and unavoidable causal link between an authority's documented intentions and its vulnerability to a legal challenge.

This chain has three critical links:

1. Section 19: The Assessment Methodology. The Act (Procurement Act 2023 c. 52, s. 19) mandates that a contracting authority must set out its assessment methodology in the tender notice. This is the authority's promise. It defines the rules of the game before the game is played.

2. Section 50: The Assessment Summary. Following an award decision, the authority must provide an "assessment summary" to all unsuccessful bidders (Procurement Act 2023 c. 52, s. 50). This is the authority's evidence. It is no longer a simple "standstill letter" with scores. It must detail how the declared methodology was applied and explain the relative advantages of the winning bid.

3. The Legal Challenge. This summary (the evidence) becomes the central exhibit for any unsuccessful bidder. If the summary fails to show a clear, logical, and robust application of the methodology (the promise), the authority is exposed. The bidder no longer needs to guess; the authority must hand over the very evidence that could be used against it.

The Solution: A US FAM-Hybrid Model with Transparent CBA

The core problem is this: how can an authority evaluate complex factors like social value, innovation, and whole-life cost under MAT, and then prove its decision-making was rational, objective, and non-discriminatory?

This is where the "US FAM hybrid tender evaluation" model excels. This approach, based on principles from the highly structured US Federal acquisition system, moves beyond the simple "price plus quality" weighting that often struggles to capture true value. Its power lies in its use of a transparent Cost-Benefit Analysis (CBA).

In this model, the authority does not just assign abstract "quality points". Instead, it quantifies the value of the non-cost elements of a bid. It works by:

• Monetising Value: As far as possible, the methodology establishes a clear formula for converting qualitative benefits (like carbon reduction, supplier innovation, or reduced user disruption) into a tangible, monetary value.

• Defining Trade-offs: Where monetisation is not possible, the methodology creates a clear, structured trade-off mechanism. It defines how much extra quality (e.g., a 10% performance increase) is worth how much extra cost.

• Total Value Assessment: The final evaluation combines the tender price with the quantified value of its technical and social benefits, resulting in a single "net value" figure for each bid.

How This Model Secures the Causal Chain

This transparent CBA approach directly addresses the three-step causal chain, transforming it from a vulnerability into a robust line of defence.

1. Securing the Section 19 Methodology By selecting a transparent CBA model, the authority is declaring a methodology that is inherently objective and data-driven. The "rules of the game" are not just subjective headings like "Quality 40%"; they are the specific formulas and trade-off ratios that will be used. This creates a powerful, auditable framework from day one.

2. Bullet-Proofing the Section 50 Summary This is where the model delivers its greatest value. When it comes time to write the assessment summary, the authority is not scrambling to compose a subjective narrative. It simply "shows the maths".

The summary can state, in clear terms:

"Whilst your bid was £50,000 cheaper, the successful tender was assessed as delivering £250,000 in quantified whole-life cost savings and £100,000 in additional, quantified social value, in direct accordance with the CBA methodology published in the tender notice. This resulted in a superior net value of £300,000, representing the Most Advantageous Tender."

This summary is factual, objective, and directly tied to the declared methodology.

3. Neutralising the Legal Challenge An unsuccessful bidder receiving this summary has a very different legal calculation to make. Their challenge can no longer be "we believe our quality was arbitrarily under-scored". They must instead attempt to prove that the authority incorrectly applied its own, published formula, a far more difficult and specific claim to substantiate.

The transparent CBA model creates the "golden thread" of logic that PA23 demands. It connects the S.19 promise to the S.50 evidence with an unbroken, mathematical line, ensuring that the authority’s choice of the "Most Advantageous Tender" is not just a defensible decision, but a demonstrably correct one.

Citations

• Procurement Act 2023 (c. 52). (2023). Available at: https://www.legislation.gov.uk/ukpga/2023/52/contents/enacted (Accessed: 16 November 2025).