Ever since becoming the MP for Reigate, twenty years ago, I have been concerned about Green Belt policy, the constituency being wholly within London’s Green Belt.

This priority is not only driven by the need to preserve the rural aspect and outstanding natural beauty of the area, but is also driven by a belief in the very principles behind the setting up of green belt designated areas around large urban conurbations.

The aim of modern Green Belts was set out in a government circular of 1955, namely to contain cities from unwieldly expansion, especially London. Apart from the key function of preventing urban sprawl, the Green Belt also provides agricultural land local to highly populated markets, open space for urban dwellers for recreation, and a wildlife resource which retains the natural ecosystem and may be otherwise at risk of being lost.

Much Green Belt land is not especially scenic and much of it is already developed, but what’s being protected are green fields in the Green Belt from development, i.e. the enclosure of open space. The consequence of green field development is that it creates a gradual eroding of the entire designated open space which leads to diminution of the Green Belt over time.

Since 1955, new towns have had to be built as overspill beyond the Green Belt but there has also been continuous pressure to reduce the Green Belt to allow building in that valuable space. This pressure is particularly strong in the current environment of a UK housing shortage and the Government’s resulting new homes targets.

It is entirely possible to address the UK’s housing shortage, and that of the South East of England, by means other than allowing or encouraging development on green fields in the Green Belt. Government policy should encourage the development of industrial and employment sites in other parts of the country, rather than in London or areas that do not have the capacity to develop sufficient new housing and infrastructure. It is largely for this reason that I objected to a second runway being built at Gatwick Airport. It simply does not have the transport or development land capacity to employ and support the number of additional employees, travellers and support infrastructure that such a development would require. Furthermore, with the advance of technology, the reasons for certain industries and their employees being based in areas close to large urban centres has diminished.

All of which brings me to UK housing policy. The Government is currently consulting on its Housing White Paper, and I am working with the Campaign for the Protection of Rural England (CPRE) to prepare a joint response to this with other MPs whose constituencies fall within the London Green Belt. It will be important for us not only to press the government to honour long-held assumptions about Conservative policy towards the Green Belt, but also for there to be an acceptance that new home targets in boroughs and districts constrained from housing development by the Green Belt are not pressured into developing on that land by unrealistic new homes targets. The calculation for new housing need should include consideration of available land; developers should not be encouraged to put in speculative and highly profitable proposals to local authorities which offer to solve new homes targets in a single development, such as the garden village proposals we are currently seeing locally.

Otherwise, the Green Belt is at risk of inevitable and permanent erosion.