Just 25,000 landowners – typically members of the aristocracy and corporations – have control of half of the country, according to new data shared with the Guardian.

The findings show that owners such as the Duke of Buccleuch, the Queen, several large grouse moor estates and the entrepreneur James Dyson own an “astonishingly unequal” proportion of the country.

If land were distributed evenly across the entire population, each person would have almost an acre – an area roughly the size of Parliament Square in central London. As it is land has fallen into the hands of a small number of owners, with tens of thousands taking the share of millions.

Guy Shrubsole, author of the book in which the figures are revealed, Who Owns England?, argues that the findings show a picture that has not changed for centuries.

“Most people remain unaware of quite how much land is owned by so few,” he writes, adding: “A few thousand dukes, baronets and country squires own far more land than all of middle England put together.”

“Land ownership in England is astonishingly unequal, heavily concentrated in the hands of a tiny elite.”

According to Shrubsole the aristocracy and gentry still own around 30 per cent of England, although that figure is likely to be much higher.

Almost 20 per cent of the country is owned by corporations, some of them based overseas or in offshore jurisdictions.

Shrubsole has listed the top 100 landowning companies, which is headed by water company, United Utilities and includes several other prominent estates such as Boughton estate in Northamptonshire, belonging to the Duke of Buccleuch, the Woburn estate, which is owned by the Duke of Bedford, and the Badminton estate in Gloucestershire, owned by the Duke and Duchess of Beaufort.

Several large grouse moor estates and Beeswax Dyson Farming, a farm owned by pro-Brexit businessman James Dyson, are also high on the list.

Jon Trickett, Labour MP and shadow minister for the Cabinet Office, said: “The dramatic concentration of land ownership is an inescapable reminder that ours is a country for the few and not the many.

“It’s simply not right that aristocrats, whose families have owned the same areas of land for centuries, and large corporations exercise more influence over local neighbourhoods – in both urban and rural areas – than the people who live there.

“Land is a source of wealth, it impacts on house prices, it is a source of food and it can provide enjoyment for millions of people.”