The Results

The Ground Penetrating Radar (GPR) scan results were finalised and the report edited over the subsequent months, and the range of initial findings are listed below. It is important to note that a GPR survey of this patchwork nature has never been attempted before (certainly not in Perth, likely not in Scotland and possibly not even in UK), the data presents a formidable challenge both in terms of assembling it into a meaningful visual composite of results but also in terms of interpreting what the data means. Consequently, it remains unclear what many of the anomalies relate to (natural or human-made) and if they are traces of human activity鈥痶hen whether they are modern or historic, and when in history they may date from.  

The findings note: 

  • At the upper levels/shallower depths, the survey helps to map subterranean utility and waste-water infrastructure, which is incredibly useful for city planning and residents alike.
  • Of particular interest at deeper levels are a series of parallel linear trends and zones of high amplitude (a response that may indicate buried structural remains or surfaces) near the junction of King St and Victoria St (Group A1). These occur at considerable depth (beginning around 1.5m and continuing down beyond 2m) and don't align with the current street plan (established since 19th century) or any post-medieval features or boundaries recorded on earlier historical maps of Perth. It is also possible to pick up other linear trends on the same alignment and approximate depth further north on King's St near the junction with Charterhouse Lane and in the private car park below Albert Place (A2). Given their鈥痑lignment and depth, it is possible that these trends represent surviving traces of the Charterhouse Carthusian monastery. Exactly which specific buildings, ranges or other elements of the complex they relate to remains unclear.
  • There is also an interesting 90 degree return on a trend half-way up Albert Place which begins at approx. 1m depth (B), which is out of alignment with the post-medieval-modern street plan or service arrangements. This could reflect the corner of a building but whether it is from the Charterhouse is uncertain.
  • Moving up to the King James VI hospital grounds, the survey has produced a series of high amplitude linear trends and zones that complement and add greater clarity to geophysical resistance responses recorded here in 1995. The nature of the responses suggests possible structural remains which may relate to earlier iterations of the hospital/alms which once鈥痵tood here or associated drainage. The鈥痳esponses occur at depths closer to 1m so are shallower than the possible Charterhouse trends further down King Street making a medieval origin unlikely,鈥痓ut not impossible. 

Detailed map of the areas of the GPR surveying

Composite depiction of anomalies from AOC Archaeology Group report, March 2025.

Dr Lucy Dean presented an initial findings paper (co-authored by Richard Oram, Gavin Lindsay and based on AOC report) at the Archaeology Research in Progress Conference in May 2025.