Urban expansion: learning from 19th century London

Paul Collier says that African cities should learn from the example of 19th century London when it comes to housing policy. London was able to build decent housing for working people because its building regulations weren't onerously high, because landowners split their land up into separate plots for small firms to build out while retaining ownership themselves, and because the legal system of ownership and tenure was clear enough to allow building societies to lend with confidence.

All good points, but I would just a couple of things. First, 19th century London also benefitted from rapidly falling transport costs, which enabled development to take place on greenfield land. Stagnation in transport technology makes it harder to keep expanding the urban frontier and compels us to try and redevelop existing urban areas.

Also, it's not just African cities but 21st century English cities which could learn from the example of Victorian London, in particular on the land ownership front. What usually happens these days is that a developer buys a large site and then waits for the most opportune moment to develop the whole thing, which can take a long time. This arrangement means you are basically creating a local land monopolist, with all the problems that entails. Ideally, government should instead try to split the task of building the site out between a number of smaller firms, who would then be competing against each other, which should raise both the timeliness and the quality of development. Obviously this is much harder when government doesn't own the land, although the German practice of umlegung (land assembly) seems to be a reasonably close approximation.