When a land or boundary surveyor is tasked with surveying a boundary, some of the key considerations will be to establish what is meant by the term boundary. There are distinct differences between a physical boundary, a general boundary and a legal boundary.
Physical boundary
Fences, hedges, walls, watercourses and building lines are typical examples of physical boundaries and are sometimes referred to as the "boundary treatment". As dictated by the name, they form a physical presence on the land, they can be directly measured to a specified level of accuracy (down to +/-10mm or even lower if necessary) and they can carry clues about where the legal boundary lies.
A measured boundary survey is primarily concerned with the physical boundaries found on site at the time of the survey, along with any clues as to legal rights and ownership. A topographical survey will include any such physical boundaries within the survey area however they are typically surveyed to a lesser degree of accuracy and may not extend to the actual limits of land ownership. It is also important that the boundary survey includes any off site historic features which can be used to fit overlays of historic photographs and plans.
The Ordnance Survey are the national mapping agency of the UK who record and maintain a record of physical boundaries - referred to as large scale topographic mapping data. This is the underlying source of information for the vast majority of title plans recorded at Land Registry. Unfortunately the level of accuracy achieved for this data is very often inadequate for the types of boundary problems that can occur, particularly for small, residential issues where small slithers of land can be the subject of dispute.
Here is a table reproduced from Ordnance Survey, showing the results of four decades of accuracy testing on their large scale topographic mapping data. As a general guide, urban areas are typically surveyed at 1:1250, rural/agricultural areas at 1:2500 and larger areas, such as mountainous terrain at 1:10,000. Without going into the nuances of relative and absolute accuracy and RMSE, these figures may come as quite a surprise to homeowners pouring over their title plans with a scale rule.
Ordnance Survey mapping accuracies of large scale topographic mapping data
| Original survey scale | 99% confidence level | 95% confidence level | RMSE* |
| 1:1250 | |||
| Absolute accuracy | 0.9m | 0.8m | 0.5m |
| Relative accuracy | +/- 1.1m (up to 60m) | +/- 0.9m (up to 60m) | +/- 0.5m (up to 60m) |
| 1:2500 | |||
| Absolute accuracy | 2.4m | 1.9m | 1.1m |
| Relative accuracy | +/- 2.5m (up to 100m) | +/- 1.9m (up to 100m) | +/- 1.0m (up to 100m) |
| 1:10 000 | |||
| Absolute accuracy | 8.8m | 7.1m | 4.1m |
| Relative accuracy | +/- 10.1m (up to 500m) | +/- 7.7m (up to 500m) | +/- 4.0m (up to 500m) |
(Confidence level is how frequently a parameter falls within the quoted limits.) *RMSE (root mean square error) is the square root of the mean of the squares of the errors between the observations. Source: www.ordnancesurvey.co.uk/oswebsite/support/products-services.html Ordnance Survey © Crown copyright 2014
General boundary
As mentioned above, Ordnance Survey map data is typically used as the base plan for Land Registry title plans. A general boundary is routinely displayed on the plan as a red line, indicating the land that the title register refers to.
The term General Boundary has been used in the Land Registration Act 1925 and later the Land Registration Act 2002. Contrary to popular belief, the vast majority of title plans use the general boundary rule, which means it is not precise or indicative of the legal position. This does enable a comparatively fast transaction speed as land and property changes hands and effects the property industry in a positive economic way. However for those left zooming in on their neighbours new fence, or cautious developers protecting ransom strips and accesses, the answers are seldom there. An exception would be where the register records that a determined boundary has been registered and does not use the general boundary disclaimer.
However, not all boundary surveys are borne out of a dispute, where the ultimate remedy is to investigate the legal boundary and register the result. Most transfers of land can be documented for land registry purposes using existing title plans or relatively cheap ordnance survey data. In cases where land is being divided by complex geometry, where there are a lack of physical features to accurately relate the division to or where Ordnance Survey mapping is out of date, a measured boundary survey can assist with transferring the desired area of land and setting the intended new boundary.
Legal boundary
Unfortunately this is the one which is seldom known. It exists as a line of no thickness and must be established from usually a very limited pool of evidence. Where it is known, it is established on record as part of an agreement/boundary definition or as a result of legal proceedings. Legal interpretation of evidence is often a necessary part of investigating the legal boundary, and surveyors technical input can be helpful in achieving this. However legal and expert surveyor fees can prove to be disproportionately costly to the value of the land in dispute, especially when parties on either side of the dispute each instruct their own advisers.
The Boundary Disputes Protocol sets out a useful process "which seeks to ensure that neighbours exchange sufficient information in a timely manner to minimise the scope for disputes between them; and to enable any such disputes to be readily resolved, keeping costs to a minimum".
A joint approach between parties, through either a mediator or legal representatives, is more likely to result in an agreement and providing no transfer of land is occurring, the details can be recorded on the measured survey created by a land surveyor to form a boundary agreement or determined boundary, thus removing the general boundary disclaimer from the Land Registry title plan.
In practice
The high cost of boundary disputes can be attributed to the current land registration system not being comprehensive enough to determine ownership of relatively small slithers of land, which make up the bulk of residential disputes between neighbours.
When discrepancies are more obvious, a measured survey can quickly shed light on the matter and assist in negotiations moving forward. This was the case on a boundary survey near Leicester when one developer built a substation directly on an easement (shaded pink). The right of access over the land was with another developer, who required the access to service another future development.
To see more examples and read more about our services in this area, please visit our Boundary Survey page
