The urban structure of London shows, when compared to other European cities, singular qualities. The lack of a central power able to impose its will on the rest of the political agents, resulting mainly from the civil wars and Oliver Cromwell’s revolutionary period, explains the nearly total lack of large, wide, straight avenues and of baroque urban layouts. It is true that Buckingham Palace is at the end of a wide boulevard, but this one sits on a royal park, which is Crown land. It is difficult to find wide and straight streets, but for some XIXth century layouts (Belgravia), that are almost always limited to the neighborhood scale.
Today’s street structure still shows quite clearly the situation prior to the XIXth century. Compared to the opening of the Parisian boulevards, or even Madrid’s Gran Vía, Regent Street and the curve to Picaddilly Circus show, with an elegant design, a permanence of the public domain and its irregularities that can also be read as a preservation of the private realm.
This is often the result of long term surface rights rents (ground lease, tenure a bail); a part of the large British fortunes originate in this business, by renting land plots to developers for decades, and recovering full property with all its content at the end of the term. Buying a home in these areas is not properly a buy, as it can be subject to this limit. This explains the uniformity of some zones, and also the persistence of the street grid.
On the other side there is also a substantial social housing stock; a part of it has been transferred to private hands from the 1980s. The system remains anyway mainly rent-oriented.
The structure of London is so the result of the overlay of a large river, a set of canals whose role is minor from the advent of the rail, a rail system whose technical demands have made it one of the main alterations of the urban fabric in the last 200 years, the presence of the large royal parks as the main public spaces of the city, and a street grid that has adapted to other conditions and has not had such a directive role as in other cities.