Why Infrastructure Projects Fail Before Construction Begins: The Workforce Problem

By Ben Mckimm

Part two of a series. In “What Infrastructure Project Failures Actually Teach Us,” we looked at how projects like Crossrail and HS2 unravelled through scope creep, cost overrun and governance failures. This instalment looks at the layer underneath all of that: whether there were enough of the right people, in the right roles, at the right time, to deliver the plan in the first place.

The Question That Gets Asked Too Late

Most infrastructure programmes are scrutinised on budget, schedule and scope from day one. Far fewer are scrutinised on workforce capacity with the same rigour, even though a shortage of skilled people can undo a programme just as thoroughly as a funding gap. By the time a client or contractor asks “do we actually have enough qualified people to deliver this,” the answer is often already no, and the programme has been built around an assumption that never held.

This is not a hypothetical risk. It is measurable, and the numbers for the UK are stark.

The Scale of the Gap

The Construction Industry Training Board's Workforce Outlook for 2026 to 2030 puts a figure on what the industry already senses: the sector needs an average of 41,200 additional workers every year for the next five years, more than 206,000 people in total, just to keep pace with demand. That is before accounting for growth. Looking further out to 2035, CITB and Skills England analysis suggests demand across the 30 most critical construction occupations will rise by close to half a million roles, while nearly 600,000 existing workers are expected to leave the industry through retirement and career change over the same period. Put those two figures together and the industry needs to attract close to a million new workers within a decade, simply to hold its current capacity.

Infrastructure sits at the sharp end of this. Water, energy, rail and transport programmes are long-term, technically demanding and increasingly dependent on a workforce that is shrinking rather than growing.

An Ageing Workforce, Retiring on Schedule

The demographic picture makes the shortage harder to fix quickly. Across UK construction, 35% of the workforce is now over 50, compared with just 20% under 30. In engineering specifically, roughly one in seven workers is now over 60. These are not abstract statistics. They translate into specific, sector-level warnings: up to 90,000 workers are expected to leave the rail sector through retirement or attrition by 2030, and in the water industry, close to a quarter of engineers are expected to retire within five years, with a much larger share saying they plan to leave the sector altogether within three.

When experienced people leave in this volume, a project does not just lose headcount. It loses the people who know why a design was changed on a previous scheme, which supplier reliably meets deadlines, and how to read the early signs that a subcontractor is about to fall behind. That kind of institutional knowledge rarely transfers cleanly, and infrastructure programmes, which can run for a decade or more, are especially exposed when it walks out the door faster than it can be replaced.

Why This Is a Planning Failure, Not Just a Recruitment One

It is tempting to treat workforce shortages as a hiring problem to be solved later, once the programme is under way. That instinct is the same one we highlighted in the first part of this series: the belief that today's gaps can be fixed during execution. Workforce planning suffers from exactly the same trap.

A business case built on the assumption that experienced site engineers, quantity surveyors or planners will simply be available when needed is a business case built on hope. When that assumption fails, the consequences are familiar: programmes stretch timelines to accommodate a thinner team, quality suffers under pressure, and the roles hardest to backfill, senior technical and commercial positions, are exactly the ones that carry the most risk if left vacant or filled with someone who is not quite ready for the scope.

This is why workforce planning belongs in the same conversation as feasibility, funding and consenting, not bolted on afterwards. A programme that has mapped its critical roles, understood where the market is thinnest, and built in lead time to secure the right people is in a fundamentally stronger position than one that discovers the gap once mobilisation is already under way.

What Actually Moves the Needle

There is no single fix for a shortage this size, but there are levers that genuinely help, and they tend to work best in combination.

Apprenticeships and structured entry routes. CITB and Skills England are both clear that Level 2 and 3 technical and vocational pathways are central to closing the gap, and colleges are reporting strong demand for construction courses. The pipeline of interest exists. The bottleneck is turning that interest into structured, funded routes into the industry, and giving employers the confidence to invest in people who will not be fully productive for a year or two.

Retention alongside recruitment. Bringing new people in matters less if experienced staff keep leaving. That means genuinely listening to why people leave technical infrastructure roles, whether it is pay, progression, project variety or simply burnout from chronic understaffing, and addressing the answer rather than just the symptom.

Knowledge transfer before it is too late. With such a large cohort approaching retirement, pairing experienced staff with less experienced colleagues on live projects, rather than leaving this to chance, is one of the more cost-effective ways to protect institutional knowledge before it disappears.

Honest workforce mapping at the planning stage. Before a programme is costed and scheduled, someone needs to ask which roles are genuinely scarce in the current market, where the organisation is exposed if a single person leaves, and how long it realistically takes to fill that gap. That is a delivery risk assessment, not an HR exercise, and it belongs in the same room as the engineers and the funders.

The Thread Running Through Both Parts of This Series

Crossrail and HS2 taught us that infrastructure projects rarely fail because of one dramatic event. They fail through an accumulation of smaller problems, each manageable on its own, that compound because nobody was tracking them closely enough, early enough. Workforce capacity is one of those problems, and it is one of the few that is visible years in advance if anyone chooses to look.

The organisations that treat their people pipeline as a core part of project planning, not an afterthought to be sorted once the ground has been broken, are the ones giving their programmes the best chance of actually reaching the finish line they set out to reach.

If you are trying to work out where your programme is exposed on workforce capacity, or you need to build a team that can carry a scheme through from feasibility to completion, we would be glad to talk it through.