The Constitution Unit


Constituency Boundary Reviews

Boundary review

The boundaries of parliamentary constituencies in the UK are reviewed periodically to ensure that constituencies are broadly equal in numbers of eligible voters while also respecting local ties. In May 2020, the government proposed changes to the system of reviewing Westminster constituencies through the Parliamentary Constituencies Bill. Responding to this, the Unit has launched a small research project examining the proposals. Led by Alan Renwick and Robert Hazell, this focuses on safeguarding the review process from any danger of undue political interference.

The bill proposes to end parliament’s ability to veto the boundaries that are proposed by the four national Boundary Commissions. Our research concludes that this is a welcome step. Current arrangements violate the independence principle. There are no such veto rights in comparable democracies such as Canada, Australia, and New Zealand.

But the research also finds that stronger safeguards are needed to protect the Boundary Commissions from interference by government. While we have seen no evidence of such interference to date, it would be possible under existing rules, and the removal of the parliamentary veto may increase incentives for it. Stronger safeguards already exist for many other bodies, notably the Local Government Boundary Commission for England. In particular, we propose that Boundary Commissioners should serve non-renewable terms, so that they are less susceptible to pressure, and that rules for their appointment should be set down in law.

This work builds on Robert Hazell’s review for the government of the Local Government Commission in 1998 [Unit report no 30], which recommended merger with the Parliamentary Boundary Commission. The Unit has also done work on the independence and accountability of constitutional watchdogs [Unit reports nos 100 and 144], and on improving parliamentary scrutiny of public appointments [Unit report no 175].

Project findings are presented in three forms:

The analysis has been cited in key parliamentary debates on the bill: