It has been difficult, more recently impossible, to expand housing supply in England, especially in the areas of greatest need.

The main cities have been surrounded since the 1950s by ‘green’ belts, in which new developments are not possible and planning consents are routinely denied by local authorities.

The extent of these so-called green belts is enormous – fully 12% of the land area is sterilised against development and it is not randomly selected.

The sterilised land is perversely in the areas of greatest housing shortage, creating a severe affordability crisis, especially in London.

The city is encircled by the M25 motorway, most of which is around 30 kilometres from the centre. What would naturally have been the outer suburbs of London, the zone outside the M25 to a distance of a further 40 or 50 kilometres at some points, is effectively off limits for new housing.

Oxford is around 90 kilometres to the west and two-thirds of the area in between is either built-up already or in the green belt, some parts of which even intrude inside the M25.

There is now a de facto green belt around Dublin, a much smaller city than London (population 1.5 million versus almost 10 million)

Development pressure is intense in the towns just outside the green belt, but is resisted locally.

Cities like Birmingham, Bristol, Leeds, Manchester and Sheffield also have green belts, inhabited mainly by better-off Conservative voters, whose representatives are resolutely opposed to more housing development.

This situation has arisen largely as a consequence of the Town and Country Planning Act of 1947, which was the template for the 1963 Planning and Development Act in Ireland.

Dublin’s green belt

The result has been, with a lag of two decades or so, a very similar crisis of housing affordability in this country.

There is now a de facto green belt around Dublin, a much smaller city than London (population 1.5 million versus almost 10 million), with strident opposition to proposals for residential zoning in what ought to be the outer suburbs.

There is housing shortage too in the main provincial centres, but the problem is most acute in the capital.

Dublin now has lower population density than other large European cities, less than a quarter the figure for the inner area of Paris, not a high-rise city and one which sustains a decent public transport system, which is not a coincidence.

Dublin’s ring road, the M50, is much closer to the centre than the London equivalent, around 10 to 12 kilometres versus 30 or so, but the effect of restrictive zoning is the same.

The area outside the M50 contains rolling prairies of undeveloped land through which the city’s displaced commuters must journey through from the distant towns of mid- and north-Leinster.

According to the 2022 Census report on commuting, released just before Christmas, the residents of Kildare and Meath have 17% and 19% facing work commutes of 60 minutes and upwards, compared to 8% in the Dublin city area.

Politicians who decry the housing affordability crisis nonetheless oppose every proposal to build closer to the city, as do their counterparts in England.

But the Dublin city area contains numerous smaller parcels of undeveloped land and the outer area, within shorter commuting distance, contains enough empty land to build another city.

The sales price of new housing in Dublin began to diverge from the figures in provincial centres only around 1975, coincident with the full impact of the new zoning rules when the 1963 legislation began to bite.

In popular discourse, the prerogatives of local authorities as the gate-keepers for land-use planning are regularly defended as an example of local democracy.

But they often operate, as in England, as the conduit for conferring veto power on local residents against the slow expansion of the growing city into the adjoining areas.

The result is urban sprawl and long-distance commuting through the vacant land where the suburbs ought to be. There is no textbook on urban planning that recommends cities with the shape which has emerged in Dublin, or increasingly in the larger provincial centres. Or in England, which first established the model which Ireland has chosen to follow.

The Dublin city area contains numerous smaller parcels of undeveloped land and the outer area, within shorter commuting distance, contains enough empty land to build another city

The crisis in housing affordability in Ireland is not yet a nationwide problem – there are large areas of the country, especially outside Leinster, where new units can be delivered at costs, which are within the budget of would-be homeowners on average incomes.

In Dublin, this is no longer the case, and there is a creeping fatalism that the situation will never be remedied.

It would be a political convulsion to curtail the role of local authorities, the gate-keepers of land-use planning, in the interests of more practical urban design, and would provoke howls of protest from defenders of what they identify as local democracy.

This process has begun to play out in England, where the opposition Labour party has committed to a review of the green belt arrangements.