Catalogue description Ordnance Survey: Boundaries Branch: Boundary Perambulation Cards

This series contains Boundary Perambulation Cards (BPC) for England, Scotland and Wales, and a small number of sample sheets of Temporary Survey Documents (TSD).

Public Boundaries are not visible structures and can only be accurately determined by relating them to features on the ground (preferably those with some degree of permanence). The surveyor determines (or ascertains) the relationship between the boundary and ground features marked on the latest mapping. This process is 'mereing' and involves not only surveying and ascertaining the boundary, but also obtaining agreement to the legal boundary line on the ground with all other relevant parties, and describing the boundary in relation to the existing physical features. The results of this work is indicated on the surveyor's map as 'mereings'.

Boundary perambulation is the act of walking the new and old boundaries to establish the ground features available for mereing. New boundaries will not have been mered before, whereas in the case of old boundaries, being re-examined for map revision purposes, perambulation will confirm that the ground features shown still exist. If they do not then the published map detail is corrected and the boundary marked as 'defaced' (Def) to indicate that the former relationship with the boundary has gone. The purpose of the perambulation is therefore to adjust the mereings to the altered state of any changed ground features.

Changes to public boundaries are made or approved by Parliament. The necessary Acts and Orders are issued by the relevant government department and supplied (with related Deposited Maps) to the Ordnance Survey. Orders define boundaries, but not in absolute terms. They instruct the Ordnance Survey to mere the boundary for that purpose. Ordnance Survey (OS) is required to mere new boundaries and the OS Surveyor is the person authorised to do this.

The Boundary Perambulation Cards are prepared by the Ordnance Survey Boundaries Branch at basic survey scale (i.e. a scale at which maps at other scales can be derived) but only for areas where there is a public boundary. They are the most important documents passed to the boundary surveyor in the field; and remain the key document throughout the public boundary perambulation and mereing process.

They are normal printed Ordnance Survey map sheets at either 1:1250, 1:2500 or 1:10,000 scale onto which Boundary Branch staff have added the relevant current boundary information which will be operative at a future date. They are used by the surveyors to obtain the information which enables them to perambulate and mere a new boundary; they carry the relevant stamps and signatures to certificate the new boundary and they act as the record of the agreed legal boundary alignment in the future.

The face of the Boundary Perambulation Card shows the original interpretation from the Deposited Map referred to in the Order and any points that may have arisen in the draft stages of the Order itself:

• new boundaries are plotted in red pencil;
• old boundaries, including mereings, are as printed (or added in blue pencil as necessary);
• all appropriate administrative names and boundary descriptions are as printed or as amended in red ink;
• obsolete information is cancelled in red ink;
• current symbolisation of the boundaries is indicated.

On the reverse is recorded the titles and dates of the Acts and Orders authorising change from the previous revision or survey, together with their operative dates; details of certification for publication of new boundaries; and other stamped details as necessary, with provision for initialling and dating of each action taken.

Once the new boundary has been mered and certificated for publication the legal boundary is established; the Boundary Perambulation Card becomes the statutory record of the mereing of the new boundary; and the alignment can be applied to revised mapping.

Deposited Maps for England and Wales are in OS 38

Deposited Maps for Scotland are in OS 39

Field files and county files Series III containing boundary making orders are in OS 77

Ordnance Survey of Great Britain, Boundaries Branch, 1849-

in 2010 Ordnance Survey

J R S Booth, Public Boundaries and Ordnance Survey 1840-1980 (Southampton, Ordnance Survey, 1980) is a full account of the work of the Boundaries Branch. It contains a useful glossary and a complete key to authorised abbreviations.