Why don't we let single streets vote to give every house on the street permission to extend – or even replace?
That would quickly generate tens of thousands of additional flats and terraced houses, especially near transport hubs, where the need for more homes is greatest.
Half of the homes in London are in buildings of just one or two floors. Bloomsbury is much taller – often four or five storeys – but much more attractive than many low-rise streets.
There are endless miles of semi-detached and detached homes whose owners would be thrilled to get permission to extend upwards, forwards or sideways. If the street can choose a design code for the extensions, it could often make the street much prettier.
There are also plenty of terraced homes that could be improved with a well-designed additional floor with a mansard roof.
If the permissions are granted to every house on the street, every owner benefits from the increased value of their house due to the planning permissions, even if they do not actually do the extension. They could always sell to someone who does need a bigger home (or to a small builder who wants to create several flats) and then save the spare money for their retirement or to help their children pay for housing.
The best way to do it would be with safeguards for the houses beyond the back gardens and for houses on street corners. We'll write more details later.
If you ask people whether every house on their street should be allowed to extend to add new flats or homes, they often say yes. Building on a street mainly affects other people on the street. It should be up to them.