The site specific methodology was as follows: i. The watching brief was maintained during the removal of all deposits down to the impact depth of the works, and/or the natural geology. ii. Overburden was removed by a mini-excavator machine fitted with a toothless bucket. iii. The exposed deposits were sufficiently clean, to allow for the identification of archaeological features or deposits. iv. A written watching brief record was made of all the observed areas and all deposits encountered were issued with unique context numbers, and context recording was in accordance with established best practice and the OA Field Manual. v. All observed areas and sections were marked on a plan tied into the Ordnance Survey data for the area. vi. Digital photographs were taken of the representative sections and deposits, and of the watching brief in general. In June 2018 Oxford Archaeology undertook a watching brief on behalf of Thames Water Ltd in the grounds of a sewage treatment works at Mill Lane, Chipping Warden, Northamptonshire. The watching brief was undertaken on trenches excavated for new duct and pipework routes. No archaeological deposits or finds were encountered. Modern truncation and disturbance was observed in several of the trenches.