The government’s latest high-speed rail spectacular is a masterclass in fiscal fantasy. A new London-Edinburgh line promising 90-minute travel times? On paper, it’s a commuter’s nirvana. In reality, it’s a £80bn gamble that will leave taxpayers holding the ticket for decades of cost overruns.

Let’s start with the numbers, because the bottom line is all that matters. The initial estimated cost of £40bn has already doubled before a single sleeper is laid. History does not forgive railway optimism: HS2’s budget ballooned from £37bn to over £100bn. This new line will follow the same script. Ministers will blame inflation, supply chain shocks, and NIMBYs. I blame a system that treats public money as Monopoly cash.

Market signals are already flashing red. Gilt yields have crept higher as the market prices in more debt issuance. The bond vigilantes are stirring. If the government plans to finance this via borrowing, it will crowd out productive private investment and stoke inflationary pressures. The Bank of England will have to keep rates higher for longer. Capital will flee to safer havens. This is not speculation; it’s basic supply and demand.

The rationale? ‘Connectivity’ and ‘levelling up’. Vague political slogans that ignore economic gravity. The north-south divide persists not because of train speeds but because of structural disadvantages in skills, housing, and business environment. Subsidising a faster rail link is like putting lipstick on a pig: it won’t fix the underlying distortions.

Consider the alternatives. Instead of pouring billions into steel and concrete, why not invest in digital infrastructure that actually boosts productivity? Or cut corporation tax to attract capital? But no, the political class loves ribbon-cutting ceremonies. They love being seen as visionaries. The rest of us see the bill.

There’s also the environmental angle, trotted out like a tired prop. ‘It gets cars off the road,’ they say. But the embodied carbon in construction will take centuries to offset. And when the line eventually operates, the energy mix still relies on gas. Green virtue is a convenient mask for fiscal incontinence.

Let’s not ignore the capital flight risk. International investors already view UK fiscal discipline with suspicion. A project of this magnitude, with such poor historical precedent, will accelerate the exodus. The pound will weaken. Import costs will rise. The working poor will bear the brunt.

In short, this is a confidence trick wrapped in a train set. The City will not be fooled. The market will punish imprudence. And when the next crisis hits, the government will have no fiscal headroom.

My advice: watch the gilt market. If yields spike, the party is over. Until then, the government will keep spending other people’s money. It’s their favourite pastime.