I fed a few of the papers and some HS2 specific ones (will share later) into claude for a summary of the papers:
The four root causes (NIC framework, endorsed by Stewart Review)
The NIC identifies four systemic root causes, and the Stewart Review explicitly endorses this framework. All four must be addressed together — the NIC is clear that government providing strategic direction is "foundational" and without it the other reforms won't reliably work.
Root cause 1: Lack of clear strategic direction
The UK's stop-start approach to infrastructure investment destroys the conditions needed for efficient delivery. When the pipeline is uncertain, contractors price in risk, don't invest in skills or capital equipment, treat each project as discrete, and the workforce fragments. The NIC contrasts this with offshore wind, where the Contracts for Difference model provided long-term funding certainty and costs fell by two-thirds between 2015 and 2022. For rail electrification specifically, the UK's intermittent approach created a workforce deficit of 1,000–2,000 people per year and a 12% salary premium, while Germany's steady programme achieves materially lower unit costs.
The PwC benchmarking study found the same pattern internationally: countries with multi-year high-speed rail programmes benefited from continuity of client professionals, industry investment, innovation, and historical data for risk allowances. The UK's approach produces the opposite — a fragmented industry with low investment, low productivity, and high overhead.
The Stewart Review recommends that NISTA be given overall leadership of the UK infrastructure programme (R79) and that a dedicated Minister for Infrastructure and Construction be considered (R78). Stewart also notes that the regulated sectors, particularly energy, have a better delivery track record, suggesting private funding and leadership structures like the RAB model bring beneficial discipline. The construction sector workforce has shrunk by 340,000 workers (14%) between 2019 and 2023, with older workers leaving and too few younger workers joining — a problem the NIC says will worsen without action.
Root cause 2: Client and sponsor challenges
The NIC's analysis found that over 50% of available cost reductions require action before construction begins. The pattern across the documents is consistent: budgets are set too early on immature designs, requirements aren't iterated against affordability, and then reality forces expensive redesign during construction.
The Stewart Review provides the sharpest HS2-specific evidence. Stewart found that "a culture of driving down cost to manage affordability has been absent from the Programme." Requirements and scope were owned by DfT but cost and schedule by HS2 Ltd, with inadequate iteration between them. Political decisions drove scope changes without robust cost challenge. Stewart recommends using a Financial Shareholder to challenge political decision-making that impacts cost (R43), requiring time to iterate requirements, scope, design and cost before committing (R42, R46), and establishing a Project Controls sub-board to scrutinise cost forecasts (R45).
The NAO's HS2 update provides the contract-level detail. HS2's main works civils contracts incentivised contractors to prioritise schedule over cost management. There was little commercial consequence for starting construction before design was confirmed, and complex design assurance processes led to fragmented design work that increased costs. HS2 Ltd had limited cost information from the supply chain, reducing its ability to assess which cost increases were genuinely necessary.
The PwC benchmarking study found that comparator projects internationally established affordability constraints at an early stage and incorporated cost considerations into all alignment, design and scope decisions. PwC concluded that HS2 Phase Two would benefit significantly from an affordability target established through rigorous understanding of the assets to be delivered — something that was notably absent.
The NAO's mega-projects report adds a governance dimension: the standard model where a single department is accountable often fails at mega scale. Where views differ between departments and HM Treasury about the purpose of a project, decision-making suffers. The NAO recommends defining a formal "mega-project" category with different governance requirements, potentially with HM Treasury or NISTA having a formal position on the project board during early stages. Stewart reinforces this with the structural observation that projects can become too big for a single entity to manage — HS2 Ltd's scope of responsibilities could have been reduced, for example by using a separate delivery structure for Euston.
Root cause 3: Inefficient consenting and compliance
The NIC provides unusually specific evidence. NSIP approvals increased by 65% between 2012 and 2022, reaching an average of about four years and over five and a half years in complex cases. The proportion of schemes subject to judicial review spiked to 58% from a long-term average of around 10%. Even after HS2's hybrid bill, more than 8,000 further consents were required from local authorities, the Environment Agency, and Natural England. The Lower Thames Crossing planning application alone cost £267m, illustrating the direct cost of the consenting system itself.
The NIC identifies structural problems: the system has become more complex and contested; individual actors are aligned to their own organisational objectives rather than the overarching goal; and late design changes driven by compliance add costs during construction. Delay is expensive in its own right — the NIC cites the A428 scheme where a one-year delay from a meritless legal challenge imposed £24m in inflationary costs with no design change. The NIC's earlier study proposed solutions that could reduce consent times from four years to two.
The Stewart Review endorses the government's September 2024 proposed reforms to planning, noting that without significant reform, major projects will continue to face cost and schedule delay. The NAO's mega-project report adds that the ICE found immature designs and consents "greatly contributed to cost escalation on HS2" and recommended that sponsors must be "ruthless in gate reviews" until design and planning are sufficiently mature.
Root cause 4: Constrained supply chain
The UK is an international outlier in the fragmentation of its construction sector. The NIC reports approximately 23,000 companies in civil engineering, nearly 90% employing fewer than eight people. Tier one contractors commonly use 50–70 subcontractors per project. The PwC benchmarking study found this fragmentation drives a 12% cost difference compared to less fragmented international comparators, through layered administration costs, profits, and risk premiums at each tier. The NIC's analysis shows that multiple layers of subcontracting overheads can make up more than 50% of a project's total cost.
The Stewart Review found that HS2 stretched the civils supply market beyond its capacity and that the structure of the UK market, with Tier 1 suppliers relying heavily on outsourced design and sub-contracting, has fundamental shortcomings. Stewart recommends NISTA conduct a review of the capacity and capability of the civils construction sector (R80).
Construction sector labour productivity has flatlined for 15 years. The NIC links this directly to lack of pipeline certainty — firms can't justify investing in capital, technology, or skills without confidence in future work. Where certainty exists, the market responds: Laing O'Rourke invested in off-site manufacture for housing on the promise of a significant pipeline and achieved a 60% improvement in production rates. The Tunnelling and Underground Construction Academy, set up for Crossrail, is now training staff for other projects. The Construction Leadership Council's analysis of 20,000 projects found those with the best front-end planning had 20% lower costs and were delivered 10–15% faster.
Cross-cutting: the gold-plating and risk aversion problem
This runs through multiple documents but is articulated most powerfully in the Nuclear Regulatory Review (2025). While focused on nuclear, the review identifies three structural drivers of over-specification that apply across infrastructure. First, a culture where the system cannot reward success but can punish failure, encouraging risk aversion at every level. Second, prioritisation of process over outcomes — elaborate process serves as a protective mechanism, dispersing responsibility and reducing the need for judgement. Third, misaligned incentives — cost-plus contracts and weak competitive pressure remove incentives for efficiency, creating what the review calls "a culture of costly compliance."
The review provides striking examples: a ventilation design change during the ABWR assessment cut emissions by one ten-thousandth of the legal dose limit at enormous expense. Safety cases have become so long and complex that no single person can read and understand them. The review describes a "one-way ratchet" where regulatory complexity grows over time because no single actor has the agency to reduce it.
The NIC's evidence from rail is parallel: Network Rail identified £156m in efficiencies in its CP7 programme simply by reviewing safety standards without compromising safety. The PwC benchmarking study found HS2 Phase Two's key assets were being developed to higher specifications than comparator schemes, driving a 5% cost difference.
The nuclear review's recommended remedy — contractual mechanisms that incentivise proportionate solutions and a culture reset where outcomes matter more than process — has clear read-across to transport and other sectors.
The meta-finding: the UK knows what to do but repeatedly fails to do it
This is arguably the most important thing the documents say. The NIC notes that past studies have identified these problems but their findings have "not been applied at scale or with the consistency needed." The Stewart Review observes that the last government report on the construction sector was from 2019. The NAO's mega-projects report notes that comprehensive guidance on effective governance already exists — the problem is consistent application. The nuclear review describes a "culture of resignation" where people simply accept that projects must be slow and expensive.
Multiple documents stress that piecemeal interventions won't work. The NIC's conclusion is that "only a system wide effort targeting the root causes — rather than piecemeal interventions — will enable the UK to reap the rewards." This means reform has to be sustained across political cycles, which loops back to the foundational requirement for long-term strategic commitment.
