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In October 2020, the Burledge Hillfort Project, in partnership with GeoFlo Southwest Geophysical and Flotation Services (GeoFlo), carried out an archaeological geophysical survey over approximately 3 hectares of the interior of the Hillfort, to the north and south of the holloway. The work was funded by Historic England.

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The survey technique utilised was magnetometer (gradiometry) survey. Geological and buried manmade features/objects can cause local variations in the earth’s magnetic field, and these can be measured with a magnetometer. This type of survey can be used to effectively define areas of past human activity, and can identify two key types of archaeological features pertinent to the Hillfort. These are as follows:

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1. Buried Objects - Objects that have been heated have their magnetic properties changed (thermoremnent effects) . Features with thermoremnent magnetisation can be identified with magnetometers, meaning that objects such as brick walls, foundations, steel or clay pipes, hearths, kilns and ferrous artefacts associated with archaeology will stand out from the background magnetic levels; and

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2. Cut and earthwork features - More subtle changes in magnetisation can also be detected. Silting and deliberate infilling of ditches and pits with magnetically enhanced soil creates a relative contrast against the much lower levels of magnetism within the subsoil into which the feature is cut. Material such as subsoil and non-magnetic bedrock used to create former earthworks and walls may also be mapped as areas of lower enhancement compared to surrounding soils.

The activity identified by the survey is plotted as mapped overlay of greyscale imagery, with differing anomalies appearing as dark positive (cut) or lighter negative (earthwork) features.

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The survey was carried out in order to identify the potential presence of archaeological activity within the interior of the Hillfort ramparts and to inform the design of any future interpretive or archaeological works. The results of the survey revealed a series of linear and curvilinear anomalies on varying alignments. These were located across the interior of the site, although notable concentrations of probable archaeological activity were identified at the southern and western ends of the Hillfort.