Imagine a defence minister who questioned whether it was worth our bothering with an army. Or a business one who said things like, "If anything, I think this country has too many companies." The thought is absurd.

And yet, it seems, if you're housing minister, it's quite okay to go round suggesting that don't really need to build any more houses. We have enough of them already, don't we? Must have, all those people are clearly living somewhere.

Yesterday saw the announcement of the Wolfson Prize for economics, which this year was awarded to the best plan to revamp the idea of garden cities for the 21st century. The award is backed by Policy Exchange, a think tank not known for its rampant socialism, and its choice of subject is recognition of the fact that the housing crisis is one of the most serious economic threats currently facing this country.

In the event, the prize went to Urbed, a Manchester-based consultancy, for "Uxcester Garden City": a template showing how a generic city of 200,000 could become one of 400,000. To show how this would work in practice, it included detailed proposals for what this would mean for Oxford. (You can read more about this on the New Statesman's new sister site CityMetric.)

The plan is no doubt imperfect, because isn't everything. But it makes a big deal of building new homes near jobs, of introducing new public transport networks when you do it, and of retaining plenty of accessible green space so that Oxfordshire doesn't end up looking like Newark, New Jersey.

Can you guess how Brandon Lewis, the man tasked with solving Britain's housing crisis, responded?

We do not intend to follow the failed example of top-down eco-towns from the last [Labour] administration. We are committed to protecting the green belt from development as an important protection against urban sprawl. "Instead, we stand ready to work with communities across the country who have ideas for a new generation of garden cities and we have offered support to areas with locally supported plans that come forward.”

After I stopped spluttering with incoherent rage, I began to catalogue the problems with this statement. The first to come to mind was this: we are going to build on the greenbelt. We just are. There isn't enough brownfield land, much of what we have is contaminated in some way, and nobody is rushing forward with ways of paying to change that. If we want to ensure we have enough houses, then the green belt has to be redefined.

That, though, is okay. Firstly, you don’t need to use that much of it to build the requisite number of houses; secondly, much of the greenbelt is either useless or horrible anyway. Isolated strips of it are sites of outstanding natural beauty; but much of it is pony clubs or golf courses or ugly farmland clinging to the side of an arterial road. I spent the first 18 years of my life living within two miles of London's eastern greenbelt, and it was so bloody hideous we never used it anyway.

The biggest problem with Mr Lewis’s statement, though, is this. Local communities are never, ever going to come up with their own plans on the scale required to fix this mess. They're just not. Nobody with a view of rolling fields is ever going to suddenly decide they'd be happier with one of a housing estate; no one with a £500,000 house secretly wishes it was only worth £250,000. By expecting local people to come up with a housing plan themselves, all you do is enable those who already have homes to block any effort to help those who don’t.

The only way we're going to solve this is if central government takes action. The coalition, in fairness, has recognised this, and in 2012 it imposed a legal requirement on councils to come up with plans for meeting local housing need. If there was any chance they would do this themselves, it presumably wouldn’t have bothered.

It’s not altogether clear that Brandon Lewis knows any of this. His one job, his only function in this government, is to come up with a plan to deal with our near existential crisis level of housing shortage. This is his purpose, this is what he's for.

But, when presented with a thoughtful plan like Uxcester, his instantaneous, kneejerk response is to trash it. At a time of massive, national housing crisis, we find ourselves in possession of a housing minister who doesn't want to build houses. He’s about as useful as an asbestos sugar bowl.

Next year, Britain will have a tight general election in which every vote matters. Oxford West & Abdingdon is a key Tory/LibDem marginal. These are facts which probably weigh quite heavily on Brandon Lewis's mind.

But the fact remains that it is his job to ensure this country has enough houses, and he’s just made it abundantly clear that he doesn’t want to do it. If he can't even be nice about a theoretical plan like Uxcester, then what hope is there he could ever take real action? If this is how he sees the world, then what exactly is Brandon Lewis for?