As read on The Economist:
“Today’s boom is much bigger. It is stoked by soaring demand for office space from expanding businesses and even greater pressure for housing, driven by gentrification and population growth. A shortage of land in a city constrained by a tight green belt makes it profitable to build upwards. Foreign money—whether from Arab sovereign-wealth funds or wealthy Malaysian investors who buy flats before they are built—means there is plenty of finance for risky projects. And the authorities, for reasons both idealistic and pragmatic, are minded to allow construction.
In theory, the London Plan, laid out by the mayor’s office, determines the city’s shape. Tall buildings are encouraged in a few “opportunity areas”, especially if they are architecturally striking, explains Sir Edward Lister, the capital’s head of planning. The plan also protects views of St Paul’s Cathedral and the Palace of Westminster, as seen from London’s larger parks. You must, for example, be able to see both buildings from a specific oak tree on Hampstead Heath. Erecting tall buildings behind them is discouraged, too.
These protected views help to explain why tall buildings are rising in such a dispersed pattern. The Shard will not get neighbours anytime soon, as it is wedged between two viewing corridors. In the City, towers are scattered instead of crowding around transport hubs, as economic theory might predict. Their odd designs—described by nicknames such as the Gherkin, the Walkie Talkie and the Cheesegrater—are in some cases a means of avoiding imposing on St Paul’s. Only at Canary Wharf, which is too far east to spoil many views, do cuboid skyscrapers rub together in the way they do in other big cities.”