The following describes a potential methodology for establishing the extent of “grey belt” using a geometrical approach to settlements within London’s metropolitan green belt.
1. This example uses Brentwood in Essex. The settlement is entirely enclosed by London’s metropolitan green belt.
In this diagram the orange colour shows the extent of Brentwood which is not within this green belt.
2. Creating a new boundary around the furthest extents of Brentwood’s boundary.
This identifies those areas which do not contribute to the five purposes of the green belt according to the NPPF. These areas could be developed without the settlement encroaching into the countryside.
3. To ensure that neighbouring settlements are prevented from “merging”, establish a 250m buffer where no development should occur.
Should this distance vary depending on the nature of the landscape? Is 250m too great, or too little?
4. Those areas within easy access of a station should also be developable, provided that this does not encroach on the buffer zone established above. Here, this has been set at 1,600m from existing stations: approximately 5 minute’s cycle ride.
4. Subtracting the geometries above, arrive at a net area which is contained entirely by the outer extents of the settlement, but excludes those areas not covered by green belt protection.
5. From this area remove any protected habitats such as SSSIs, Ancient Woodlands, Areas of Outstanding Natural Beauty, and so on.
6. Here the final geometry is shown with an 800m / 10-minute walking distance and 1,600m 5-minute cycle distance.
7. And then overlaid onto a satellite photo of Brentwood, showing the landscape around the town which could be considered as grey belt.
