Shaun Spiers is Executive Director of Green Alliance and Chair of Greener UK, a coalition of 13 environmental groups working on Brexit.

For almost 40 years, governments have pulled off the difficult trick of building too few houses while building over too much countryside. For 13 years of those years, I was chief executive of the Campaign to Protect Rural England (CPRE) and in the thick of some fierce battles over housing and planning. My book, How to build houses and save the countryside, reflects on why we build too few homes, why planning battles are so acrimonious, and what to do about it.

In writing the book I had two audiences in mind: those who deny there is a housing shortage or claim it is easy to solve (‘build somewhere else’, ‘put all the homes up north – the home counties are full’, ‘build them all on brownfield sites’); and those who feel no grief when countryside is lost, particularly the ‘ordinary’ countryside round towns and cities, and who think that the housing crisis will be easy to solve if we only make it easier to build on greenfield land (aka countryside).

The latter were heavily influenced by a long and successful war on the planning system started by Gordon Brown and intensified by George Osborne. The housing crisis came to be framed as a planning problem. The solution was less planning and more land, particularly Green Belt land near the major cities: if only that was provided, and NIMBYs faced down, all would be well.

But successive waves of planning liberalisation failed to achieve the desired results. Housing targets were increased and land was released to meet them, but still the market – well, the market served the market, not the Government. It is surprising that anyone was surprised by this.

In retrospect it is odd that everyone spent years arguing about housing targets and the proposed location of new homes, rather than asking who was going to build them. What should have been a debate about ‘our failed housing market’, to quote the title of the 2017 housing white paper, became an argument about planning.

Those fixating on planning wilfully ignored the most obvious cause of the decline in building rates: the fact that around 40 years ago, the state stopped building houses. For 30 years after the Second World War, when more than 200,000 homes were built every year in the UK, local authorities built at least 100,000 of them. Between 1951 and 1979, 48 per cent of new homes were built for social rent. Politicians competed over who could build more. Now they wring their hands and make speeches about housing ambition. The public sector has ceased to build in significant numbers, and the private sector has not made up the shortfall. Thus, in large part, the housing crisis.

The planning system does bear some responsibility for this failure, but its failings are not those set out in countless influential reports from Policy Exchange and other centre right think-tanks. The problem is not too much planning, but too little. The 1947 planning system, passed by Attlee’s government but devised by card-carrying Conservatives, had two sides. It constrained development and it ensured a plentiful supply of development land at reasonable prices. Land contributed only around one per cent of the cost of a new home in Milton Keynes when it was first developed.

It is worth recalling the role of Conservatives in this story. Milton Keynes was first proposed by Buckinghamshire County Council (not a Socialist stronghold) as a way of stopping sporadic development across the county. And land value capture was at the heart of wartime debates about reconstruction. In a March 1944 broadcast, Churchill promised that “ample land” would be made available at pre-war values. Local authorities would be able “to secure any land required for the reconstruction of our towns and cities”. Churchill’s speech recalls a time when what was identified as a housing crisis prompted muscular action by the state.

We might now be returning to such a time, though (rightly) with more generous compensation for landowners than Churchill envisaged. Over the last couple of years much of the best thinking on land value capture has come from Daniel Bentley at the centre right think-tank, Civitas. Toby Lloyd, formerly of Shelter and co-author of a pioneering study of the economics of land is now the Prime Minister’s housing adviser, an inspired appointment. And this thinking has influenced Gavin Barwell, Ruth Davidson, Nick Boles and others.

Conservatives are also talking about who will build the homes we need. Nick Boles says “we are never going to get to 300,000 [new homes] a year unless the state is building 100,000 a year”. Lord (Gary) Porter makes a strong case for allowing local authorities to build. Richard Bacon wants 60,000 custom-built homes a year in the UK, which would go a long way to reviving small building firms.

Few now regard planning liberalisation as the solution, and this shift in thinking is welcome. But it must be accompanied by three things.

First, a recognition that countryside is precious. It is not acceptable that the majority of new homes are built on greenfield land at lower densities than were achieved by John Major’s government 25 years ago. For those Conservatives who do not feel this in their bones, I recommend a dose Roger Scruton, or at least some effort at empathy. Saying that “all” we need to do is build over two or three percent more of countryside or Green Belt, as if places do not matter, will not get houses built: it will just stoke resistance.

Second, a serious effort to strengthen a planning system that has been so knocked about that it is barely able to do its job. Many local authorities are hardly planning at all. Squeezed between central government demanding housing numbers (what happened to the Conservative critique of Labour’s targets culture?) and developers looking to build the most profitable homes on the most profitable (greenfield) sites, in many places the system has lost all credibility. It has certainly lost its ability to create beautiful developments that enhance places rather than eroding them.

Above all, if the housing crisis is to be cracked in ways that maximise the use of brownfield land and the potential for urban regeneration, rather than anodyne, car-dependent estates sprawling into the countryside, it will require the government’s wholehearted attention. The 1951 Conservative manifesto described housing as “the first of the social services”, and gave it a priority second only to national defence. The Government’s priority now is, inevitably, Brexit. But once that great experiment is complete, we will need a switch from huffing and puffing about housing to actually building houses.