Parliamentary Constituencies Act 2020

Overview of the Act

Reproduced verbatim from the Explanatory Notes published with the Act on legislation.gov.uk (Crown Copyright, Open Government Licence v3.0). Explanatory Notes are prepared by the responsible government department and are not part of the Act.

The principal legislation governing parliamentary constituencies and boundary reviews is the Parliamentary Constituencies Act 1986 ("the 1986 Act"). The Parliamentary Constituencies Act 2020 amends the 1986 Act and makes provision in respect of: the number of parliamentary constituencies; the rules governing the setting of the boundaries of parliamentary constituencies; the conduct of boundary reviews by the Boundary Commissions; and the process for bringing the Boundary Commissions’ recommendations into effect.

The existing parliamentary constituencies in England are based on data from 2000; those in Scotland, Wales and Northern Ireland are based on data from 2001-2003. In effect, the current constituencies reflect how the UK population was at the beginning of the century and do not reflect changes in demographics, house building and migration.

Also, as a consequence of earlier legislation, there is currently a significant difference between the sizes of the electorate in many parliamentary constituencies.

The combined effect of this amending legislation and the retained elements of the 1986 Act will allow the Government to meet one of its 2019 Manifesto commitments - to "ensure we have updated and equal Parliamentary boundaries" and to do so on the basis of 650 constituencies.