03/02/2017 05:26 GMT | Updated 02/02/2018 05:12 GMT

Why Are There So Many Abandoned Buildings In London?

Abandoned buildings are everywhere. You may be sitting in one right now. That's quite unlikely. But you may be closer to one than you think, especially if you are reading this in London.

By 'abandoned buildings', I don't mean when people leave their homes unoccupied to go to work; I mean officially abandoned, vacant and derelict buildings. Nobody ever goes in, nobody ever comes out. And none of them are filled with chocolate, presidential-looking dwarves and a recently deceased cinema icon (RIP Gene Wilder). One estimate says that permanently empty commercial property in London could be replaced by up to 420,000 homes.

The abandoned buildings of London are documented on blogs like Derelict London, which host haunting images of these buildings trapped in time. Many urban explorers have followed suit, seeking out undiscovered vacant properties to take eerie photographs of their own.

But in a city of constant renovation, how do these buildings become abandoned? And why have they been left unoccupied long enough for Instagram-addicted hipsters to come along and snap them in the first place?

They are unnecessary

In years gone by, well-meaning developers have overstepped the mark, erecting new buildings for absolutely no reason. More frequently, buildings simply lose their purpose--no wonder millennials can relate.

This is what happened with North End Station, which was nearly finished in the 1950s until the developers decided it was too close to Golders Green and abandoned its construction. It now sits unloved and unaccessible to all but the most ardent urban explorers. I am not ardent enough to have visited.

There is also the huge sailmakers loft in Limehouse, active from 1889 to 1972, when people realised there wasn't a huge market for sails anymore.Buildings like these lost their use and never gained a new purpose, thus becoming the abandoned structures we know today.

They are of historical interest, preserved but not generally open to the public

Some buildings become abandoned, but are kept in good condition for reasons of historical conservation.

Much like North End Station above, Down Street Station opened in 1907 but closed in 1932 because people were happy to walk to Hyde Park Corner or Green Park, which were both very close to it. During WWII Winston Churchill (of meaty £5 note fame) used the station as a shelter. The site is preserved so the public can visit on guided tours, and presumably so Theresa May has somewhere to hide out if things go south with the whole Trump thing.

Another historically-preserved-but-still-abandoned building in London is the Strand Union Workhouse, which was recently given Grade II listing because, as Paul Talling explains on Derelict London, it is thought to be "the best preserved Georgian-era workhouse in London." This means the building's historical significance has to be taken into account if it is renovated, and that the owner now needs to ensure the building is secure.

As Talling told the Express, "Sometimes people do break into these old buildings, listed buildings or places which have historical value, spraying graffiti and that sort of thing." Yet, while specialists Oaksure Property Protection explain that steel screens, boarding up and manned guarding are some of the most effective ways to ensure vacant buildings are safe from intruders, it is the imperative of the very people who have left these buildings empty to provide protective measures for their safety.

They are sitting there as investments

What about the buildings that are not that historically significant? The derelict schools that could become new schools, or flats. The derelict police stations that could become new police stations, or flats. Not to mention the old, derelict flats that could definitely become flats. Why are these still abandoned? That question can be answered with one word: Money.

Many abandoned buildings are essentially squatted by their owners who are just waiting for their value to increase before selling them on. This is nowhere more evident than on one of London's most expensive but emptiest streets: The Bishop's Avenue, aka Billionaires Row.

Billionaires Row is home to the biggest luxury mansions in the city, which are valued up to £16,000,000 each. Further examination of the price figures shows that their values have increased significantly in recent years. House number 38, for example, was sold for £3,750,000 in 1998. It is now worth an estimated £16,310,000. That's an increase of 400% in just 18 years. But as revealed in a Guardian report from 2014, most of these mansions are as run down as the creepiest locations on the Derelict London blog, some unoccupied for decades.

With over 8,000 homeless people in London, it's time to think about whether some of these abandoned buildings could be put to better use than lining the pockets of the non-residents of Billionaires Row.