Sixth Periodic Review of Westminster constituencies

The Sixth Periodic Review of Westminster constituencies, also known as the 2013 Review, 2018 Review, or just boundary changes, is the process by which parliamentary constituencies to the House of Commons of the United Kingdom are being reviewed by the four UK boundary commissions, to comply with the revised rules for the number and size of constituencies introduced by the Coalition government. The process was intended to be completed by 2015 and is now expected to be completed by 2018.

Following a debate in the House of Lords on 14 January 2013, an amendment to alter the relevant legislation to change the date by which the Sixth Review should be completed was passed by the Lords with a majority of 69 votes. This was the expected result given opposition by Labour and latterly, the Liberal Democrat party to the legislation.

A subsequent Commons vote on 29 January 2013 meant a new review will instead begin in 2015 for completion in 2018. The boundary commissions announced the cancellation of the reviews on 31 January 2013. Whilst the Review was required to be completed by October 2013 (by virtue of Section 3 of the Parliamentary Constituencies Act 1986 as amended by the Part 2 of the Parliamentary Voting System and Constituencies Act 2011), the Electoral Registration and Administration Act 2013 amended the Parliamentary Constituencies and Voting System Act, delaying the review until 2018.

Following the 2015 election it was reported that the majority Conservative government considered the boundary review as a priority.

In July 2015, Prime Minister David Cameron reiterated his plan to "cut the cost of politics" by going ahead with reducing the number of Members of Parliament. He said the proposals were "the right approach".

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