CPRE is right that parts of the Green Belt are wonderful assets, and most of it should be retained. Our newest trustee Tristram Hunt is a big fan of the Green Belt.
But I’m not sure the Green Belt should remain quite so sacrosanct. Opening up just a bit of it to development could help solve our housing supply problem.
Like it or not, the demand for housing space is going to rise. The UK population is projected to reach 70 million within 20 years. And although we've only just nudged our way out of recession, income growth and demand for new development will resume at some point. Unless we are content to see housing become ever more unaffordable, we need to give more land over to housing.
So, should we consider using some of the Green Belt for that new housing?
Here are some facts - which might surprise you. England's 14 Green Belts cover 1.6 million hectares - nearly 13% of the entire land mass. By contrast, only 10% of England is officially "built up" – and domestic gardens are four-tenths of that.
Imagine the whole of England is a football pitch. All the built up land is the penalty area. Most of this is made up of gardens, roads, paths and railways. Houses and non-domestic buildings would cover just half the centre circle.
Unlike other protected sites like National Parks, not all Green Belt land is of high environmental quality - nor is all of it that accessible. CPRE tells us that 18% is classified as ‘neglected’.
Open space is essential. But shouldn’t we put a higher priority on protecting high-quality open space in the middle of our cities, where people can access it - rather than at the outer fringes of the city, where they can’t?
The current Green Belt rules mean that city residents face higher house prices and more over-crowding, but reap few of the benefits. The biggest winners are property-owners in the shires.Green Belts have largely succeeded in their primary aim, to contain urban sprawl. But they are preventing the economic growth of cities like Cambridge, Oxford and London - the cities that will do most to drive the UK economy.