Langham Pond, at Runnymede, is a wonderfully rich Flagship Pond with a long history and some very rare inhabitants. Managed by the National Trust, Runnymede has three main ponds that all lie along the line of an ancient braided channel of the River Thames. That channel was abandoned sometime in the last 500 years and gradually silted up. Of the three ponds, Langham Pond is undoubtedly the jewel in the crown.

Langham Pond is of national importance, and supports a remarkable array of nationally rare species. Its uncommon plants include Greater Water-Parsnip (Sium latifolium), Tubular Water-dropwort (Oenanthe fistulosa) and Marsh Stitchwort (Stellaria palustris), and a long list of plants that are Red listed in England such as Round-fruited Rush (Juncus compressus) and Frogbit (Hydrocharis morsus-ranae) – the latter an exceptionally uncommon plant in south east England. Langham Pond is also purported to be one of only two UK sites for the Frogbit smut (Tracya hydrocharidis) and one of very few UK sites for Metopomyza ornate – a leaf-mining fly of the beautiful Flowering Rush (Butomus umbellatus). There are also past records of a healthy population of the scarce Variable Damselfly (Coenagrion pulchellum).