What SDWH does
SDWH Limited is a consulting practice founded by Matthew Rees. It provides independent, objective research, analysis and briefing to organisations operating at the intersection of business, finance and government.
The public sector regularly undertakes transactions and decisions — asset sales, major procurements, infrastructure financing, governance reforms — that carry significant financial risks and opportunities. These decisions require a combination of commercial acumen, financial literacy and an understanding of public sector accountability that is difficult to find in a single source. Whether you are seeking to make the case for bold value-orientated policy decisions, evaluating the optimal strategy, or reviewing past performance, SDWH provides independent analytical insight to support that process.
The SDWH difference
Most analytical input comes from one direction: investment banks, management consultancies, or the civil service. SDWH brings all three perspectives simultaneously. Most scrutiny is backward looking, and can result in risk aversion. SDWH is forward looking, with a proven track record in generating high impact returns on investment for delivery teams.
- Independent.No commercial interest in the outcome. No mandate to sell a product. Objective assessment of what the evidence shows.
- Forward-looking.Not a review of what went wrong, but a clear view of what should happen next and why it will generate impact.
- Grounded in evidence.Every assessment draws on direct experience of how government has handled comparable decisions, what has worked, and what the data shows.
- Impact-generative.A programme of 15 reports led by Matthew Rees has been independently validated as generating £1.7bn of financial impact — a ~250:1 return on the cost of the work. That figure includes £1,372m attributed to the UK Guarantees Scheme for Infrastructure (NAO Annual Report 2024–25) and £332m from asset sales reports including the Privatisation of Royal Mail and the Sale of Eurostar (NAO Annual Report 2021–22).
Matthew Rees
Matthew Rees has spent his career working at the boundary of government and markets. He applies commercial acumen gained in accounting and investment banking to address complex commercial challenges in the public sector. Throughout his appointments including the Competition Commission, National Audit Office and the Single Source Regulations Office, he has delivered regulatory and data services to balance the interests of government and commercial counterparties, and led major examinations of how government invests for growth, supports companies to safeguard public interests, raises money from asset sales and privatisations, how it spends money through procurement, manages supply chains, and how it finances infrastructure investment. He has direct experience as an investment banking professional of valuations, M&A, privatisations, competitive auctions, special administration processes, infrastructure guarantees, defence contracting regimes, procurement frameworks and governance arrangements across central government and economic regulators.
SDWH Limited is the vehicle through which that experience is made available to organisations who need it. SDWH Limited provides research, independent analysis and briefing that helps organisations understand how government has approached comparable decisions, what the evidence shows about what works, and what questions they should be asking. SDWH Limited does not lead transactions, does not provide regulated financial advice and does not provide statutory audit services.
Focus areas
Who we work with
SDWH works with a focused range of clients across the accountability and governance landscape. The common thread is that they are operating under scrutiny pressure — or they should be — and they need analytical support that is independent, fast and credible.
Private offices and senior accounting officer teams
Permanent secretaries, directors general and accounting officers preparing for Public Accounts Committee sessions face a distinctive challenge: they must defend decisions taken across large, complex programmes in front of a committee with access to an independent NAO report, a detailed question script and a public audience. The stakes are high, the time for preparation is short, and the conventional briefing process rarely stress-tests positions robustly enough.
SDWH can provide independent pre-PAC challenge: working through the lines of accountability and the financial evidence in the way the committee will, identifying weaknesses, sharpening the answers, and helping witnesses understand how the accountability cycle works from the outside. SDWH is also developing a regular analytical briefing — tracking the NAO work programme, PAC inquiry schedule and Treasury Minute responses — available to subscribers who want to stay ahead of the accountability cycle.
First-time PAC witnesses
Not all PAC witnesses are career civil servants who have been through the process before. Accounting officers from arm's-length bodies, delivery agencies, private sector contractors, trade bodies and consumer representatives can find themselves appearing before the PAC without a deep understanding of the committee's working methods, the standard of financial challenge they will face, or the conventions governing witness conduct.
SDWH offers focused preparation sessions for first-time witnesses — explaining the format, the standard of evidence the committee applies, and the typical lines of challenge for the relevant programme or topic. These sessions are delivered confidentially and without any conflict of interest with the committee or the NAO.
Supreme Audit Institutions in the home nations and British Dependent Territories
The audit offices of Scotland, Wales, Northern Ireland and the British Overseas Territories each operate within a distinct constitutional and financial framework, but share a common interest in high-quality evaluative methodology and in producing reports that drive genuine change. Demand for value-for-money and performance audit capability is growing, and the techniques available are advancing rapidly.
SDWH can support SAI teams in designing and delivering complex evaluative reports — drawing on direct experience of leading major value-for-money examinations at the NAO, including the analytical techniques, evidence standards and public interest framing that produce durable findings and lasting impact.
Supreme Audit Institutions internationally
Many SAIs around the world look to the UK NAO model as a reference point for accountability and evaluative methodology. Understanding how that system actually works — the relationship between the Comptroller and Auditor General, the NAO, the PAC and the Treasury Minute — and how it has evolved, is not straightforward from the outside.
SDWH can provide briefings, teach-ins and structured training on how the UK public accountability system operates, what its strengths and limitations are, and what transferable lessons it offers. These sessions can be delivered online, in-person, or through formal training partnerships with institutions such as CIPFA or the Civil Service College.
The UK Parliament
Parliament has a broader accountability function than the PAC alone. Select committees across the full range of policy areas — including business, defence, transport, and constitutional affairs — scrutinise decisions that have significant financial and commercial dimensions, sometimes without the support of an NAO report as a base.
SDWH can support parliamentary teams with independent analytical input for commercial and financial scrutiny — providing a credible outside perspective on the evidence, the questions that need answering, and the quality of the government's response. SDWH can also provide analytical context for bodies that oversee the accountability system itself, including those considering the market for audit and accountability services.
Accountability at pace — applying rigour under pressure
The UK's current fiscal position, and the pace at which public money is committed and spent, means that the conventional accountability process — NAO report, PAC inquiry, Government Response — lacks agility.
SDWH is developing a faster, more targeted approach to accountability challenge: independent analytical scrutiny conducted at the pace that decisions are made, not in the rearview mirror. The most useful analogy is red-teaming — independent, structured challenge of live proposals and decisions by someone with no stake in the outcome, delivered quickly enough to change course before commitment. This model is well established in defence and cybersecurity; it is largely absent from the spending and commercial governance of public programmes.
Whether you are a minister's team seeking external challenge of a major business case, a select committee wanting a rapid independent view of a commercial decision, or a political party developing a programme to identify and recover public value at scale, SDWH can provide the analytical rigour without the institutional deference.
Get in touch
SDWH Limited works with a small number of clients in order to maintain quality and objectivity. If you have a challenge that sits at the intersection of business, finance and government, get in touch.