UK Parliamentary Constituencies

This website provides information on the changing composition of parliamentary constituencies in the United Kingdom since 1885.  Have you ever wanted to know at a glance:

• How constituencies created at each boundary review have been related to their predecessors?

• The changing picture of General Election results in each part of the country?

• For any precise location, which constituencies it has been in over time?

Every constituency that has existed since 1885 has been allocated to one of 111 groups. All these groups have now been updated to reflect the constituencies introduced at the 2024 General Election.

For each group there are separate charts, maps and tables:

(a) Constituency Charts.  These charts show how the constituencies have evolved over time with transfers of electors between them.  The size of transfer is indicated by the format of the line between constituencies, and very small transfers are omitted.  Only years in which there are changes affecting the constituencies in the group are shown in the chart.  Transfers that are to or from another group of constituencies are shown to or from boxes with a dashed border.

(b) Election Results Tables.  These tables show the outcome of every general election since 1885 for the constituencies shown in the chart above, colour-coded according to the main party groupings.

(c) Area Maps and Tables.  There may be more than one map per group of constituencies to provide clarity.  Each map divides the area covered into distinct sub-areas, each of which has had a different sequence of constituencies in which it has been since 1885.  There is a table for each map which acts as a key.  The tables also show an estimate of the relative size of the electorate in each sub-area denoted on the map.

More detailed information on the presentation and methodology can be found in the information section.  Note that historic constituencies shown in a Constituency Chart may have covered a geographical area that is shown on more than one Area Map.

Transfer size estimates.
Estimates of how each constituency following every review is related to its predecessors are contained in three sets of master spreadsheets covering England & Wales, Scotland and Northern Ireland.  These are available for download here.

Constituency maps.
Maps for the whole of Great Britain and Northern Ireland are available here.  There is also the ability to download the underlying data, so that it can be used in other projects.

This website is continuously being updated. For a list of the latest changes please see the changelog.