Yesterday’s report from the Campaign to Protect Rural England about the brownfield land with space for a million homes perfectly illustrates the organisation’s many strengths, and its weaknesses.

With exquisite attention to detail, it demonstrates that there are unused sites in London with the potential for 170,000 homes. Someone has done a lot of work.

CPRE has been extraordinarily successful in preventing existing cities from sprawling further. It is the most powerful force against building homes in the countryside.

Where it has been weaker, sadly, is in recognising the appalling scale of our housing crisis, and the damage to average wages, the environment, opportunity and fairness caused by our epic shortage of homes within easy reach of the best jobs.

CPRE already has considerable planning expertise to support its members in their fight against homes on the green belt, but it has yet to hire a single economist.

The total price of the UK’s housing stock exceeds the cost of building it by some four trillion pounds, or two-fifths of the entire net worth of the United Kingdom, according to the latest available Office for National Statistics data. If CPRE employed a real, research-driven economist, they would explain that is a sign of scarcity on an epic, and profoundly harmful, scale.

It is entirely possible to admit the terrifying extent of our housing shortage and yet insist that it should be met within existing city boundaries, so long as you have a way to get enough homes built in those places.But our current system gets nowhere near to doing that. In fact, it has never built remotely near enough flats – no more than 100,000 a year, less than a third of what we need. Nothing short of a substantial upgrade will do the job.