The Green Belt is a very raw topic, and it would be difficult to see any wide-spread development of any kind without significant fallout. There is still a lot of former industrial land across London that is ripe for development before consideration could be given for indiscriminate construction across the Green Belt. A lot of the post-WW2 estates could also be redeveloped to substantially raise the density of certain neighbourhoods. And if things really did start getting tight, a lot of the pre-war semi-detached homes that dominate Outer London could be redeveloped on a large scale.
Certain locations within London which are in the Green Belt do however offer scope for targeted development. The image below is of Crews Hill in the London Borough of Enfield; it is dominated by agricultural land, with the remainder of the area composed of woodlands, a golf course, public gardening centres and some nestled residential properties. Crews Hill station (clearly visible at the centre top of the image) is served by 3tph into Moorgate throughout the week (2tph on weekends); Transport for London are keen to boost take over the line and increase frequencies further. Yet development around the station is very limited, as are car parking facilities. Crews Hill demonstrates the issues around the Green Belt, namely that is rather nonchalant in its coverage regardless of the suitability for potential development.
Source: Bing Maps
There are some tube stations on the Central Line (Barkingside, Fairlop, Grange Hill and Theydon Bois [pictured below]), Piccadilly Line (Cockfosters and Oakwood) which are directly adjacent to Green Belt agricultural land. There are countless others which are within 100m of Green Belt land.
Source: Bing Maps
Going beyond London – but still in the Green Belt – there are some peculiar situations where entire commuter towns are constructed on one side of the tracks. Take Harlow – pictured below – a post-war New Town built to rehouse Londoners who lost their home during the Blitz. Yet all of the town was built on one side of the tracks, admittedly part of that is due to the River Stort floodplain, but Harlow is just over 30 minutes train journey to Central London. With sufficient flood relief, it would be possible to construct thousands of residential units on the other side of the tracks. There are other examples where areas adjacent to a heavy rail station are not optimised due to the Green Belt.
Source: Bing Maps
Another discussion point is that of golf courses; they consume a lot of land in and around London, and sometimes in prime locations that would make far better sense for alternative uses. Consider the area in south-west London bordered by the District Line, South West Main Line, Reading to Waterloo Line and Kingston Loop Line; there are ten golf courses within this area. That isn’t to say that all these parcels of land ought to be concreted over, but golfing is a niche activity that consumes a disproportionate amount of land. Outside of London, the situation gets even more silly; Surrey which directly borders south-west London has more land dedicated to golf courses than homes.
Which then brings me onto HS2 which will be a massive disruptor. HS2 will be a high-capacity, high-frequency HSR network; the first in Europe and comparable to the Beijing-Shanghai HSR and Tōkaidō Shinkansen. Take Birmingham; property prices are two thirds cheaper than those in London, and with HS2 the city – the second largest in the UK – will be just 49mins from London. Birmingham and other cities connected to HS2 could thus take a lot of residential construction relief away from London, whilst offering a viable commuting option to the British capital. HS2 also frees up a significant number of paths into Euston, King’s Cross and St Pancras that HS2 and thus open up further development opportunities in current commuter towns in the regions.
Relocating Heathrow to the Thames Estuary has been openly discussed for several decades, but if it were to, it would unlock the potential for hundreds of thousands of residential units, all within London and with excellent transport connections. One other side point of HS2 is that it also helps provide relief to another major issue facing London; the lack of aviation capacity; Birmingham International Airport and Manchester Airport will be just 39mins and 59mins respectively from Central London with HS2.