scrub between the Colne River and Denham Way. It has a variety of breeding birds and its status is described as favourable. Coppermill Down The SSSI includes a 6 hectare field east of the Grand Union Canal described in the Natural England citation as Coppermill Down, although it is not known by that name locally. It is one of the few remaining examples of unimproved chalk grassland in Greater London, and is notable for the pyramidal orchid and the bee orchid. Its status in September 2011 was described as 'unfavourable declining' due to inadequate grazing. The field is crossed by a footpath between Jacks Lane and Park Lane. High Speed 2 Proposed high speed railway High Speed 2 between, initially, London and the Midlands if built will cut across a corner of the site on a viaduct. Natural England commented that there would be a serious loss of ancient woodland and a potentially damaging indirect impact on Broadwater Lake. See also List of Sites of Special Scientific Interest in Greater London List of Sites of Special Scientific Interest in Buckinghamshire References Sites of Special Scientific Interest in London Sites of Special Scientific Interest in Buckinghamshire Nature reserves in the London Borough of Hillingdon Parks and open spaces in the London Borough of Hillingdon Herts and Middlesex Wildlife Trust reserves