[pjc50]

It's hardly the most expensive land on the planet, it isn't even all that near to London let alone somewhere like Manhattan or Hong Kong.

Food security is not something that should be entirely handwaved away, although I agree that plenty of places manage to live entirely on imports.

I agree with the idea of not limiting ourselves to a few cities: that's why it makes little sense to try to turn Cambridge into a London suburb. It's a market town of historic buildings that was spared bombing. The tech industry growth there is great but somewhat accidental. I doubt you've been there, but there's very little that can be done about the traffic problems without demolishing a college. The building of a new railway station north of the river should help greatly though.

I'd suggest trying to build up tech industry in one of the 'post-industrial' cities instead. Maybe we could buy up the £1 houses in Stoke-on-Trent and market those to China at huge markups instead.