Version 1: Conservative peer Lord Wolfson - a prominent Conservative supporter, who donated to David Cameron's 2005 leadership campaign - offers a £250,000 prize for a new garden city, preferably with a precise location, and - small detail - please "avoid relying on a single penny of public money". To help things along, former Downing Street planning adviser Miles Gibson has taken a career break from the civil service to run the project.
Version 2: soon after, Ed Miliband - who'd set up a commission under former BBC Trust chairman Sir Michael Lyons to show how Labour would double housing output to 200,000 a year - announces a dramatic plan to build five new towns along High Speed 2. Brilliant, because some would presumably be north of Birmingham, where there's political support for HS2. Even more brilliant, this could help shift the HS2 benefits out from the big core cities into the surrounding regions (this column, 29 November).
Notice the linguistic twist: the Labour vision is a 21st-century version of 1940s-style new towns, built by public development corporations. Lord Adonis has stressed that the Attlee government passed the 1946 New Towns Act a year after being elected, and immediately started building. Labour sees the Wolfson Prize as a political smokescreen to divert media and public attention away from the real issue, which is how these places get built.
All standard party political fare, you might say. But consider deeper issues. Those first-generation new towns were built with public money not merely for basic infrastructure, but also for the homes, which were public housing at affordable rents. But that public investment eventually generated huge sums from commercial and industrial development, making the whole operation profitable for the taxpayer. Second-generation new towns like Milton Keynes, completed under Margaret Thatcher, had lots of privately-built homes for sale. The development corporation produced master plans and told private builders that if they followed the plans they'd make more money. They did - and came back for more.
The Financial Times last week reported that George Osborne's two-year campaign to build public infrastructure with private money had largely failed. So that "not a penny" promise may ring hollow. So maybe David Cameron should borrow Ed Miliband's model instead?
Sir Peter Hall is Bartlett professor of planning and regeneration, University College London.