The Parliamentary Voting System and Constituencies Act 2011 created new rules for the redistribution of seats and reduced the House of Commons by 50 Members. Professor Ron Johnston in Bristol's School of Geographical Sciences was a key advisor throughout the development of this legislation. His recent work has investigated and promoted amendments to produce more politically-acceptable rules.

The four independent and non-partisan Boundary Commissions - England, Scotland, Wales and Northern Ireland – have been responsible for defining and recommending constituency boundaries to Parliament every 8 to 12 years.

In 1995, Johnston led a major grant with co-investigators Dr David Rossiter and Professor Charles Pattie, to look at these boundaries and their impact on election outcomes. Among the major outputs of this research, the team developed a method to analyse bias in UK election results. They subsequently applied this method to show that there had been much greater bias in the 1997, 2001 and 2005 elections than previously - and that it had favoured Labour.

'Labour won the 1997 election easily partly because the system was biased toward them by over 100 seats,' explained Johnston.' If the Conservatives and Labour had got the same percentage of votes then, Labour would have got at least 100 more seats.'

Introduction of a new Bill

The Conservatives wanted to change the existing Rules for Redistribution to ensure greater equality and remove part of the rationale for this bias.

They began discussing this with experts, including Johnston, in 2009. Over the next year, the research conducted by Johnston and his colleagues, and the advice and oral evidence they provided, informed the crafting of the legislation.

When the Bill was published in 2010, the British Academy Policy Centre promptly released a monograph co-authored by Johnston, which provided context and a critique of the Bill. This monograph was widely cited during debates in both the House of Commons and the House of Lords.

'It became one of the most debated topics in the House of Lords,' said Johnston. 'All three parties trusted my neutrality, so I was involved in almost daily discussions with them to advise how the new rules could be amended to get better equality in the electorates while retaining the situation whereby MPs represented identifiable communities.'

During this time, Johnston was also called upon by the media to help improve the public's understanding of the Bill. His impartial expertise injected facts and clarity into the public discussion.

Dramatically altering constituency makeup

Enactment of the Bill in 2011 initiated a review by the Boundary Commissions using the new Rules for Redistribution. The Commissions had to give greater priority to making the constituencies equal in size and less priority to existing community structures, which had taken priority prior to the Act. Johnston and his colleagues evaluated the Commissions’ proposed boundaries under the new rules and quantified the extent of disruption; it was greater than it had ever been in any previous redistribution.

'Some existing constituencies disappeared, while others were cut in half,' said Johnston. 'For some MPs, this meant either that their constituency would no longer exist or that it would change dramatically. In many cases, this would mean having to build a relationship with a new constituency and perhaps one where they had no prior links.'

Reducing the disruption

In early 2013, Labour joined with the Liberal Democrats to delay implementation of the new Rules for Redistribution until the 2020 election.

In 2014, Johnston, Rossiter and Pattie published a report, Equality, Community and Continuity: Reviewing the UK Rules for Constituency Redistributions, indicating that application of the new Rules for Redistribution would be less disruptive with one significant change - if constituency electorates varied by 8 to 10 per cent around the UK average, rather than 5 per cent.

Their report was launched in Parliament with sponsorship from senior members of the three main political parties. In response, the House of Commons Political and Constitutional Reform Committee held its own inquiry and published a report, What next on the redrawing of parliamentary constituency boundaries? proposing changes in-line with those proposed to them in written and oral evidence by Johnston and his colleagues and by the Commissions. Johnston's expertise will continue to be called upon as this unfolds with the new government elected in 2015.