There is a famous l9th century Cruikshank cartoon illustrating London's army of urban invasion expanding into the countryside. Infantrymen with chimneypot bodies and mortar-filled hods for heads advance on unprotected rural land, while a kiln spews out a barrage of hot bricks on to fleeing hay ricks. The front line of Cruikshank's wickedly-observed expansion has continued outwards ever since, accelerating in the 1930s and 1960s. However, in recent years the line has held fast on that well-respected but uneasy truce, the green belt.
Geography teachers will be aware of the relevance of the study of the rural urban fringe at A-level. The Associated Examining Board, for instance, makes several such references within units on Settlement Patterns and Processes (the rural urban continuum concept and the impact of sub urbanisation on the rural urban fringe); Economic Activity and the Business World (waves of service industries into the urban fringe); Population Pressure and Resource Management (horticulture and pick-your-own on the urban fringe) and Managing Cities - Challenges and Issues (green belt policy).
Places beyond the hard urban edge have benefited from green belt policy, managing to keep themselves more or less to themselves. Look on an Ordnance Survey map: once the continuously built-up area of south-west London's outer boroughs has petered out, places such as Staines and Chertsey, Shepperton and Sunbury still remain distinct urban entities within what seems a rural setting.
But on the ground, how does this metropolitan green belt fare today in a borough such as Spelthorne? As you drive out of Staines towards Laleham village, it is difficult to appreciate the clarity of settlement at all. Where does Laleham Road, Staines, become the Staines Road, Laleham? Only occasional glimpses through the ribbon of houses on our left precedes the rural prospect you get at last from the one field remaining undeveloped.
Once through the winding core of Laleham, we are indeed in open farmland. Yet all is not what it seems. The furrows of Laleham Farm run over restored sand and gravel workings, and the high bank on the left hides much of an active in-fill site. Laleham and Littleton Park nurseries promise more conventional intensive agriculture but even here there are distinctly urban habits. An industrial unit at Laleham Nurseries offers car body repairs, while Littleton Park is already well known for monthly car boot sales and a planning permission notice on the gate announces the temporary constructio n of model film sets. For, driving on into Littleton,we enter the make-believe land of Shepperton Studios. The impermanence of a film set is not out of keeping with transient rural urban fringe land use. Even the local stream, the Ash, has doubled for a mighty African river: when Humphrey Bogart picked leeches off his legs in The African Queen he was actually wading in the River Ash.
The village of Littleton retains a church, a school and a green but any truly rural feel is lost as we skirt the steep bank of the Queen Mary Reservoir. This massive construction for a basic need was dumped on Astleham early in the century, so that no direct evidence of the hamlet remains.
The cottages we pass on our left were actually built to rehouse the locals who had to vacate their homes. On our right, behind locked gates are massive sand and gravel workings. In the untidy fields, horses graze where the fertile soil should be worked - horsiculture not horticulture.
Finally, down Charlton Lane, we drive along the archetypal urban fringe road. First a boarding kennels and a garden centre, before passing over the compulsorily purchased track of the M3. A rubbish tip and a dog breeder face a golf course and driving range, and beyond the railway line the lower meadow of the River Ash is getting "restoration". And then, quite suddenly, we are back inside another urban nucleus in Upper Halliford.
This already blighted landscape must be protected from the expanding clashes of urban need. This is what green belt policy is doing. However, the policy is more about what you cannot allow than what land uses you really want. Consequently, too much change has gone on piecemeal. Any public debate usually focuses on opposing change: the Charlton rubbish tip that we sped past is currently one of Surrey County Council's five possible sites for an incinerator, and locals feel concern.
This zone then may look somewhat rural but the pressures on it are decidedly urban. It is therefore at the forefront of contemporary pressures on the British landscape. You might well have recognised elements of this dishevelled fringe from your own background. Spelthorne Borough may not sound a pretty sight but for the geographer it is a fascinating one.
"Land Use Conflicts on the Metropolitan Fringe", led by Dr Robert Gant and Patrick Talbot is one of the fieldwork visits at the GA's annual conference on April 4
Patrick Talbot teaches geography at Hampton School