The Parliamentary Constituencies Act 2020 (c. 25) is an Act of the Parliament of the United Kingdom. It amends the regulations underpinning the parliamentary boundary review process as set out under the Parliamentary Constituencies Act 1986 and previously amended by the Northern Ireland Act 1998, Boundary Commissions Act 1992 and Parliamentary Voting System and Constituencies Act 2011.

A bill was introduced on 19 May 2020^[1] to reflect a written statement, entitled Strengthening Democracy, from the Minister of State for the Cabinet Office, Chloe Smith, on 24 March 2020.^[2] It received its Second Reading on 2 June 2020.^[3] The Parliamentary Constituencies Act 2020 received royal assent on 14 December 2020.^[4]

The main provisions of the Act are as follows:

Section 1 – Reports of the Boundary Commissions

Each Boundary Commission must submit a report:

1. before 1 July 2023,
2. before 1 October 2031, and
3. before 1 October of every eighth year after that.

Section 2 – Orders in Council giving effect to reports

Orders in Council giving effect to the reports to be automatically passed. The Orders must be made within four months of the reports being laid before Parliament, "unless there are exceptional circumstances".

Section 3 – Modifications of recommendations in reports

A Boundary Commission may submit modifications to its report after it has been submitted but before an Order in Council has been drafted.

Section 4 – Publicity and consultation

This section changes the timings of various stages in the publicity and consultation procedures.

Section 5 – Number of parliamentary constituencies

The number of constituencies remains at 650. Previously, the number was to be reduced to 600.

Section 6 – Taking account of local government boundaries

This amends the factors a Commission may take into account to include local government boundaries which are prospective on the "review date", as opposed to just being effective. Prospective local government boundaries are those which have been specified by legislation, but have not yet become effective.

Section 7 – Protected constituencies

This adds Ynys Môn (defined as the area of the Isle of Anglesey County Council) as a protected constituency.

Section 8 – Registers used to determine the "electorate" in relation to the 2023 reports

For the 2023 reports, the "electorate" calculations were to use the electoral registers published on 2 March 2020 (rather than 1 December 2020). This amendment was specifically inserted, partly because of the shorter time-frame for submitting the reports, but primarily because of concerns over collecting the data during the COVID-19 pandemic.^[3]

Section 9 – Alteration of the review date in relation to the 2023 reports

For the 2023 reports, the "review date" was specified as 1 December 2020, rather than 2 years and 10 months before the report date.

Section 10 – Removal of duty to implement etc. in relation to current reports

This section formally removes the duty to implement the previous reviews which had been submitted in September 2018.