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Caterham is the second largest conurbation in East Surrey with a population of some 14,500. The Town is situated on the side of the North Down and extends into the valley to the south and along the top of the Downs to the North. The town developed in the mid 19th century, when a branch railway line was given Royal assent in June 1854 for a line to run from Caterham to a junction with the Brighton Line - a distance of some 4 3/8 miles. The opening of this line in 1856 triggered one of the great railway disputes between the London Brighton and South Central Railway and the South Eastern Railway which prevented regular services being run until 1862.

Portley is in the parish of Caterham on the Hill, situated on the ridge of the Down. The north side of Caterham and to the South of the Battle of Britain RAF station at Kenley. It is a mainly residential area.

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