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The Parliamentary Constituencies Bill is a government bill that would amend the existing legislative framework governing the number of constituencies used in UK general elections and the periodic review of their boundaries. It would: 

  • Maintain the number of UK parliamentary constituencies at 650, reversing an earlier change that would have reduced the number of seats in the House of Commons to 600.
  • Update the rules governing how parliamentary constituency boundaries are set.
  • Amend how the UK’s four independent boundary commissions conduct reviews.
  • Change how the boundary commissions’ recommendations are brought into effect, notably by removing the current requirement for parliamentary approval before changes are implemented. 

The Parliamentary Voting System and Constituencies Act 2011, passed under the Coalition Government, stipulated that the boundary commissions should conduct future boundary reviews based on there being 600 parliamentary constituencies. The commissions subsequently submitted recommendations for new boundaries in September 2018. The Government has yet to bring forward the order required to implement the recommended changes. The general election held in December 2019 took place based on 650 constituencies. 

The Conservative Party manifesto at the election included a commitment to “ensure we have updated and equal parliamentary boundaries, making sure that every vote counts the same—a cornerstone of democracy”. In March 2020, the Government announced that it was “minded” to bring forward primary legislation to amend the framework for boundary reviews to implement this commitment. At the same time, the Government suggested that it would remove the statutory obligation to implement the 2018 boundary review recommendations and would seek to maintain 650 constituencies. It also indicated that the legislation would amend how often boundary reviews should be conducted and introduce a new ‘automatic’ system for implementing boundary changes recommended by the commissions. The latter measure would have the effect of removing Parliament’s role in approving any changes before they are made. This proved a controversial issue during MPs’ deliberations on the bill.

The bill was introduced in the House of Lords on 15 July 2020. The House is scheduled to debate the bill’s second reading on 27 July 2020.


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