In her memoirs the late Margaret Thatcher wrote that privatisation must be “at the centre of any programme of reclaiming territory for freedom”. Since 1979 British prime ministers have been true to her word. Thatcher used territory in a metaphorical sense, but it was also true literally: the privatisation of land is the biggest, and least well-known, sell-off of the state’s assets. As Brett Christophers, a professor of economic geography, points out in our pages, almost 10% of land has been transferred from public into private ownership since Thatcher came to power. In his book, The New Enclosure, Prof Christophers calculates that approximately 2 million hectares of land – or 10 % of Britain – has disappeared from public hands, the bulk of which has entered corporate, as opposed to charity or community, ownership. This is a privatisation of half of the state’s estate, worth about £400bn, and dwarfs any other transfer of public wealth to private hands.

The scale of the disposals was masked because the process took place largely in silence and by stealth. Often tracking the sales was difficult because of the opacity of transactions. The diversity of public bodies in the UK offering sites – from forests to airbases to hospital grounds – made it hard to piece together. The sales often took place at knockdown prices, with the public sector barely realising a fraction of the current value. This process has been briefly illuminated by tenacious journalism, such as this week’s story exposing how nine years of swingeing central government cuts to English councils have resulted in a vast and irreversible sell-off of public assets. In many cases local authorities have begun offloading their assets – playing fields, community centres, libraries, youth clubs, swimming pools – to fund redundancies made necessary by Whitehall cuts.

The defence of privatisation is that it can increase efficiency and spur investment. Such an argument is difficult to sustain with land. When the Cabinet Office looked into whether public bodies were holding on to vacant space, officials reported that, au contraire, it was the private sector that had a problem – maintaining a vacancy rate three times as high as government. Neither has land use been invigorated by private developers. Last year the New Economics Foundation pointed out that the government’s target of building 160,000 homes by selling off public land was 12 years behind schedule and would take until 2032 to achieve. The Tudor enclosure movement was supposed to have turbo-charged the capitalism of its day. Even if this dubious claim is true, it is unlikely that today’s equivalent is having any positive effect.

Where there appears to be some historical echo is in the appropriation of wealth by a rentier class which has grown up alongside large aristocratic estates. A staggering 23 of the top 100 richest people in the country last year have property listed as a major source of their wealth. That dwarfs the other biggest sources. Then there is the corporate hoarding of land: one study lists 50 private companies that together own about a 40th of Britain. Lastly there is the growing social dislocation: the share of young families privately renting has increased from just 9% in the late 1980s to 34%. Land can bring political influence, power, wealth and pleasure. But these things ought to be widely shared, whether land is built upon or not. It ought to be there for the common good: to be run across or gazed over or protested on.

Ownership of land matters, and it ought not to be solely for the market to decide who is included or excluded from it.