IN ITS manifesto published this morning the Labour Party is proposing sweeping changes to Britain’s infrastructure. Backed by a £250bn ($320bn) “national transformation fund”, the manifesto promises to “transform our energy systems [and upgrade] our economy”. This involves the nationalisation of the water system, the energy-supply network, Royal Mail and the railways. Britain’s infrastructure is indeed due an upgrade. But Labour’s plans would be extremely costly—both in the short and long term.

The first challenge would be to move privately held firms back into public ownership. The government might need to fork out around £65bn for the water industry, £60bn for National Grid (which runs electricity- and gas-transmission networks) and £6bn or so for Royal Mail. In reality, were Labour to win the election on June 8th the share price of those firms would probably fall as investors took fright. That would make everything cheaper. Nonetheless it is quite possible that half of the £250bn fund would be spent before Labour had been able to meet its other pledges, such as building a “Crossrail” train line for the north of England.

Nationalising the railways, by contrast, might not be especially costly. Network Rail, which manages the track, is already in public hands. The train companies have time-limited franchises. Once these have expired the government could take back control at zero cost. However, many of the franchises do not expire until the 2020s. And if the operating companies knew that they had no chance of holding on to them, they would sharply curtail investment in the short term.

More costly than the initial price of buying back these industries would be the long-term damage done to them by placing them back under public management. National ownership in the past was characterised by chronic underinvestment. A paper from the World Bank pointed out that in the six years after privatisation in 1989, Britain’s water companies invested £17bn in improving supply, compared with £9bn in the six years before privatisation. Even on the railways, which passengers readily complain about, satisfaction is higher than in the majority of European countries. The worry is that back under state control investment would dry up and productivity would stagnate.

Yet Britain’s utilities are far from perfect. On international rankings of infrastructure quality the country has slipped in recent years. Energy companies take advantage of consumers’ unwillingness to switch supplier, by charging steep prices to their most loyal customers. Water bills have risen sharply in real terms since privatisation.

There are interesting suggestions about how to improve this state of affairs. Some economists argue that the current system, where a “super-regulator” (the Competition and Markets Authority) shares competences with the sectoral regulators (such as Ofgem and Ofwat), creates confusion. Regulations are horribly complex; utility companies hire senior staff less for their ability to think creatively and more because they understand how to navigate the rules. Others argue that the government needs to deploy more aggressive techniques to get people to switch between suppliers if service is poor.

There is a need for radical thinking on how to solve these problems. Labour’s proposals, by contrast, represent merely the exhumation of policies that were buried some decades ago because they didn’t work. Far from being radical, Jeremy Corbyn’s programme is in many ways a conservative manifesto.