Set Britain’s HS2 alongside Japan’s Chūō Shinkansen and the most uncomfortable contrast is not that Britain is a little slower. It is that Britain has spent far more to build a shorter, slower railway stripped of most of its original ambition. The Chūō Shinkansen is no faultless model. It has overrun on cost and schedule, it has clashed with Shizuoka Prefecture over water resources, and it has exposed real risks in deep tunnelling and local coordination. That is precisely why the comparison bites. A Japanese line that runs largely underground, threads through mountain ranges, uses maglev technology and is designed for around 500 km/h still ends up, even after overruns, costing less than half of HS2 in total and only about 40 per cent per kilometre. Britain can no longer blame inflation, environmentalism, geology or the pandemic for what has gone wrong on HS2. The real problem is not on the construction sites. It is in the institutions, the governance, and a system that leaks value at every stage between vision and delivery.
HS2 Phase 1 runs from London to the West Midlands, around 225 kilometres with four stations, and the latest estimate now sits between £87.7 billion and £102.7 billion. The earliest section, between Old Oak Common and Birmingham Curzon Street, will not open until at least May 2036 and could slip to October 2039. Full services into London Euston are not expected before May 2040 and could be delayed to December 2043. The Chūō Shinkansen’s Shinagawa-to-Nagoya section is around 286 kilometres with six stations, roughly 86 per cent of it underground, including deep mountain tunnels, underground terminals, a maglev system and a design speed of 500 km/h. JR Central revised its cost estimate for that section in October 2025 to ¥11 trillion, roughly £52 billion at recent exchange rates. Even after that overrun, the Japanese project still works out at around £180 million per kilometre; HS2, on the upper estimate, comes in at close to £460 million per kilometre. Cost categories, exchange rates, land regimes and project scope are never strictly comparable, but the gap is too large to dismiss with a wave at “different national circumstances”.
Put the two side by side. The Japanese line is 50 kilometres longer, has two more stations, is designed to run nearly twice as fast, sits almost entirely underground, and relies on a maglev system that has yet to be proven at commercial scale. On every dimension of engineering difficulty, the Chūō Shinkansen is the harder project. Yet the timelines are roughly aligned. Japan broke ground at the end of 2014 and aims to open in 2035. Britain began main construction in 2020 and expects the first section to open between 2036 and 2039, with full services not until the early 2040s. In roughly the same twenty years, Japan is delivering a longer, faster, deeper, more complex railway with more stations. Britain is delivering a shortened, slowed, hollowed-out version of its original plan, for more than twice the price.
HS2’s deepest failure is not that it built too many tunnels. It is that it never honestly priced what surface construction actually costs in modern England. The country is densely populated, land rights are layered, local opposition is well-organised, environmental constraints are tight, and existing roads, utilities, villages, woodland and farmland are tangled together. Surface alignments look cheaper on a spreadsheet. In practice, each one drags along compensation, realignment, noise mitigation, viaducts, road diversions, utility relocation, ecological offsetting, construction traffic, local lobbying and legal challenge. The project thought it was saving money by avoiding tunnels and ended up exporting that saving into political and administrative complexity it could not control. The £100 million bat tunnel became a symbol not because protecting bats is absurd, but because it laid bare the contradiction at the heart of HS2: a high-speed rail project sinking enormous time and money into managing the resistance generated by its own decision to stay above ground.
The lesson from the Chūō Shinkansen is not that “all-tunnel is always cheaper”. It is that Japan accepted earlier a simple reality: in mountains, dense cities and high-conflict corridors, tunnelling is not a luxury but a way of containing risk. Deep tunnels are expensive, but they involve fewer interfaces, less land acquisition, less surface disruption, more direct alignments and more concentrated engineering responsibility. HS2 oscillated indefinitely between two mentalities. It wanted to be marketed as a world-class high-speed railway while still being delivered through piecemeal British compromise on every stretch of route. What it saved was not money. It was the project’s coherence, replaced by an endless chain of exceptions, fixes and redesigns.
The British government itself has now conceded that roughly two thirds of HS2’s cost increases stem from work missed from the original scope, underestimation and inefficiency, with only about a third attributable to inflation. The Stewart Review, published in 2025, was even blunter. The very ambition of building “the best and fastest” railway, it concluded, had undermined any culture of cost control; the project was “subject to evolving political aims, which pushed forward on the schedule before there was sufficient design maturity and caused progressive removals of scope”. This is no longer an engineering accident. It is institutional failure.
The irony deepens. HS2 has now reduced its top design speed from 360 km/h to 320 km/h to reduce testing, certification and commissioning risks, claiming savings of £1 billion to £2.5 billion. Lowering the speed is not necessarily wrong; 320 km/h is the established operating standard across much of mainland Europe. The fault lies in how late this realism has arrived. By the time over £40 billion had been spent in five years without a single metre of track laid, admitting that the original specification was too ambitious is no longer prudence. It is a belated patch.
Slice the failures apart and HS2 reads as the product of several British institutional habits compounding on each other. Planning procedures demand hybrid bills, environmental assessments, judicial reviews and successive rounds of public consultation; each step is reasonable on its own, ruinous in combination. NIMBYism turns every surface alignment into an exercise in compensation, rerouting, tunnel extensions and ecological remediation. Most damaging of all, specifications and scope keep changing. The northern legs of Phase 2 were cancelled in stages; the Euston station design was redrawn and then overturned; each round of “cost-saving” scope reduction created vast sunk costs that could not be recovered. The Stewart Review put it plainly: “constant scope changes, ineffective contracts and bad management” have wasted billions of pounds. Trying to cut costs through deletion has only produced more expensive losses.
Beneath all this lies a deeper problem. Britain no longer has a standing institution that accumulates expertise across major rail projects. HS2 Ltd was assembled from scratch for one project; Crossrail Ltd was wound down after the Elizabeth line opened; the next megaproject will have to recruit a new team and start over. France has SNCF Réseau, Japan has its JR companies, Spain has ADIF, Hong Kong has the MTR. These are permanent organisations that plan, build and operate over decades, so institutional memory, engineering talent and cost benchmarks build up internally. British megaprojects, by contrast, look as if every generation has to learn to walk again. The hard lessons of one project dissipate as soon as the delivery team disbands; the next project then hires new people who proceed to make a familiar set of mistakes. On top of that, government wants political wins, the Treasury wants spending control, the Department for Transport wants a coherent narrative, HS2 Ltd wants to deliver, contractors work to commercial risk clauses, consultants supply designs and cost models, and local politics keeps pushing up compensation and modification demands. Every participant can defend its own slice. No one bears the full consequence of failure as a real owner would. The Chūō Shinkansen has had its disputes too, but JR Central is both the builder and the future operator. Responsibility and commercial incentive sit inside one institution.
The implication is that, when Britain next attempts a project of this scale, it should not confine its review to a particular contractor, government or set of executives. The more direct move is to bring genuine international high-speed and long-tunnel delivery experience, from Japan, France, Switzerland, Spain and Hong Kong, into the front end of British projects in an institutionalised way. This is not about surrendering sovereignty to foreign engineers. It is about acknowledging that the domestic ecosystem has repeatedly shown it cannot deliver this class of work alone. Route choice, tunnel-versus-surface trade-offs, station scale, contract packaging, cost benchmarking, risk allocation, design freeze and operational requirements should all be subject to international independent review, with experienced foreign project leaders embedded in steering and decision-making roles, not merely producing reports as advisers. British infrastructure can no longer be settled inside a closed circle of local bureaucrats, consultants and political compromise.
HS2’s original policy logic was never absurd. British rail capacity is constrained, the West Coast Main Line has been under sustained pressure for years, and London, the Midlands and the North need a more reliable spine connecting them. The absurdity is that a project conceived to solve a capacity problem has ended up as a shorter, slower, delayed, more expensive line whose final delivered capability is still unclear. The Chūō Shinkansen is a reminder that long tunnels, high speeds and serious technical complexity are not, in themselves, unaffordable. What is unaffordable is an infrastructure system with no firm goal, no stable design, no cost discipline, no concentrated accountability and no institutional memory.
Britain has to admit that a real capability gap has opened up in the way it delivers large infrastructure. HS2’s most expensive feature may not be the track, the tunnels or the trains. It may be Britain’s residual belief that it naturally knows how to build world-class infrastructure. The evidence now says otherwise. The country still knows how to debate, consult, redesign and explain its overruns. It no longer reliably knows how to build a railway on time, on budget and to specification. That is the most uncomfortable thing to acknowledge when HS2 is set against the Chūō Shinkansen.
