Archaeology South-East (ASE) was commissioned by Sutton and East Surrey Water to undertake a programme of archaeological monitoring by Kathryn Grant, during the widening of an existing gateway to a covered reservoir at Anstiebury Camp, Coldharbour, Surrey (NGR centred 515336 144042). The watching brief monitoring was carried out in one site visit on 24th February 2012. Natural sandy geology was encountered 300mm below ground level and was overlain by subsoil and topsoil. No archaeological finds were recovered during the watching brief.