GUEST EDITORIAL | ALASTAIR SMITH, CHAIR, BRITISH TUNNELLING SOCIETY


WHERE DID THE ENGINEER GO?


Four decades on from the Channel Tunnel, our machines and our methods have never been better — so why do our major projects still overrun? The answer lies less in the ground than in what we have done to the contract and the consent, says Alastair Smith, Chair, British Tunnelling Society, in a guest editorial.


As a newly graduated tunnel engineer in 1988, I headed down to the Channel Tunnel to join the Eurotunnel Project Implementation Division on secondment from Sir William Halcrow and Partners for 18 months overseeing some amazing tunnel construction. It remains the most extraordinary hole in the ground I have ever worked in — and, let us be honest, it opened a year late and cost £9.5bn against the £4.8bn promised to its bankers in 1985, an overrun of some 80% in real terms.1


So I will not pretend


to you that there was a golden age when tunnels came in on time and on budget. There was not. What there was, however, was a fundamentally different mechanism for delivering them. Nearly four decades on, I find myself asking


whether; in fixing the faults of that era, we have built new ones into the foundations — and whether we are strangely reluctant to name them. It is worth saying plainly why tunnelling sits


apart from the rest of civil engineering. A bridge or a building is assembled from manufactured components to a design the engineer largely controls, and its principal uncertainties can be resolved before construction begins. A tunnel is the opposite: it is not so much built as won from ground we cannot fully characterise until we are inside it, however many boreholes we sink. The design is, in truth, a hypothesis about the ground — tested and revised as the face reveals what site investigation could only infer — and the works advance along a single, largely irreversible line, with little room to engineer around a surprise. Tunnelling is managed discovery, and that is exactly


why the authority to decide quickly matters more here than almost anywhere else in construction. The tunnel projects of my early career were


delivered under the ICE Conditions of Contract, with the Engineer at their heart: a named professional who designed the Works, administered the Contract and carried a duty to hold a fair balance between Employer and Contractor. When the ground surprised us — and the ground always surprises us — the Engineer had the authority to make a decision and keep the machines moving. Valuation and argument followed the work; the work did not wait for the argument. The model was imperfect. It could be paternalistic and opaque, and it concentrated great


10 | September 2026


power in one office. But it was quick, and it kept engineering judgement at the centre of the Contract. Then came Latham, Egan and the New Engineering


Contract (NEC), and much of what they brought, tunnelling needed: early warning mechanisms, programme discipline, collaboration written into contract language rather than left to goodwill. Our own industry matured alongside, bringing: the Joint Code of Practice for Risk Management of Tunnel Works, Geotechnical Baseline Reports (GBR), and a far more sophisticated conversation about ground risk than anything available in 1988. But somewhere in that transition the Engineer


quietly disappeared. The NEC Project Manager acts for the Employer, with


impartiality surviving only in the narrow duty to assess compensation events fairly. No single person in the modern contractual structure owns the whole engineering problem. In place of one accountable professional we have layered assurance — employer’s agents, delivery partners, independent certifiers, review boards — each adding cost and elapsed time, none carrying the Engineer’s old authority to decide and move on.


...THE ENGINEER HAD THE


AUTHORITY ...BUT HAS QUIETLY DISAPPEARED.


Where our recent major programmes have


struggled, it has rarely been for want of oversight bodies. On more than one, the tunnelling itself constitutes considerable engineering achievement, driven to programme and handed over without drama; the difficulties came later, in fit-out, systems integration and testing, where no single contractor was required to own its interfaces with the next and no single engineer held the whole. Billions of pounds and years of programme have been lost at those boundaries — not in the ground. And yet it is the tunnel — the portal, the launch


shaft, the boring machine — that becomes the public face of the overrun, when in truth the money was lost in the unphotogenic territory of systems, software and testing. The visible civils make the easy poster boy; the losses are too often booked elsewhere.


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