Getting Reduce and Equalise Right

5th September 2010
5 Sep 2010
boundary review
boundary changes


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Getting Reduce and Equalise Right

The Electoral Reform Society has called on government and opposition to ensure that controversial legislation to create equal-sized constituencies delivers on its promises.

Research commissioned by the Society from leading location specialists CACI demonstrates how equalising constituencies can be done fairly and equitably. CACI has deployed cutting-edge technology to show how a new political map could be drawn, and reveals how existing issues with details contained in the Parliamentary Voting System and Constituencies Bill could be resolved.

The bill is proposing a reduction of 50 seats in the House of Commons. According to the CACI’s new political map, England would lose 32 seats, Scotland 6 seats, Wales 11 seats and Northern Ireland 1 seat. The bill proposes redrawing and equalising constituency boundaries, and reducing the disparities between the size of seats. While most former counties will lose seats, Cambridgeshire, Central Scotland and Inner London would gain MPs.

The Society has urged both government and opposition to “act responsibly” and engage with the legislation to ensure that both boundary changes and the proposals for a referendum on the Alternative Vote survive.

Keith Best from the Electoral Reform Society said:

CACI has demonstrated that there is a way of equalising constituencies fairly. The bill as it stands has practical problems and human costs – none of which are insurmountable.

The government’s stated intention is to redraw constituencies and make them equal-sized. The proposed legislation, in its present form, cannot achieve this goal. Their decision to build seats using registered voters rather than the adult population is a recipe for bloated constituencies packed with invisible citizens.

Likewise the proposed ‘5% rule’ is an impossible aspiration, but both can be fixed in a heartbeat. We hope both government and opposition are prepared to take heed.”

Speaking on the AV measures contained within the bill Keith Best added:

MPs risk throwing the baby out with the bathwater with this bill. An impasse on boundary changes will only serve to deny voters their say on the Alternative Vote. The public don’t require a lesson on what happens when an irresistible force meets an immovable object - not when it’s their democracy at stake.

There are non-partisan ways of engaging with this bill, but that requires MPs on both sides of the House to act like parliamentarians. If MPs can act responsibly we can have fair seats while ensuring the public aren’t denied an historic opportunity to choose fairer votes.”

Patrick Tate, Associate Director in Location Planning at CACI, said:

We firmly believe that using the right technology is the key to providing fair and equitable parliamentary constituencies. The tools and techniques we have used for drawing constituency boundaries are deployed across a range of commercial businesses and the public sector. We have been sensitive to traditional boundaries, as well as taking into account how an area can practically be serviced by an MP.

The solution we have put forward is based on the number of people over the age of 18 in 2015, rather than the number of people registered to vote. We consider this to be a fairer approach due to fluctuations in the size of the registered electorate in different areas.”

Patrick Tate added:

The bill states that the electorate of each constituency should not be more than 5% above or below the national average. However, we have found this to be mathematically impossible* as the building blocks used to create constituencies, ie wards, are, on average, larger than the stated 5%. Adhering to the 5% rule would inevitably lead to, for the first time, split wards. The current CACI solution is based on +/-10% which in some constituencies is still a challenging target.”

Mark Harper MP, the constitutional affairs minister, has described the possible splitting of wards to reach the 5% target as ‘a trade-off…so that votes are more equal in weight.’

*The population of 18+ adults, after the Orkney & Shetland and Na h-Eileanan an Iar constituencies are removed, is approximately 51 million, giving an average size in the new 598 constituencies of 85,300. 5% of this is 4,265. But, the average ward is 5,400 which is more than 1,000 greater than the stated 5%.

Talking points

West Midlands, Merseyside and Greater Manchester will lose four seats each, while inner London will gain two seats. For a full breakdown of the parliamentary counts before and after Reduce and Equalise, please see below.

The Coalition programme includes the redrawing of constituencies to make them equal-sized. The proposed legislation, in its present form, will not achieve this goal.

After equalisation, the average constituency will contain about 76,000 registered voters. It will have a total voting age population (VAP) of about 83,000. But in areas of the country where registration is low, the VAP could be as high as 110,000 – a third bigger than the average constituency.

Both the voting system and boundaries play a role in ensuring MPs have a real mandate. With turnout in some constituencies below 50%, and First Past The Post (FPTP) delivering MPs with ‘majorities’ as low as 29%, we could feasibly have an MP representing an adult population of 110,000 people, with a mandate delivered by only tenth of the population. AV requires MPs to secure a mandate delivered by 50% of voters. The strongest possible mandate is secured by Fair Boundaries and Fairer Votes.

Based on Electoral Commission estimates as many as 3 ½ million voters could be removed from the political map under the Government’s current proposals. The CACI plan ensures those citizens are counted.
Voters from all parties are likely to suffer under current plans. Average registration levels do vary significantly by party. These figures are based on demographic data, and ward-level population (18+) and registered electorate figures.

Tendency Average Registration
Conservative 92.34%
Lib Dem 91.33%
Labour 88.57%
Source: CACI

In Northern Ireland, where individual voter registration has already been rolled out, total registration is 84.5% of VAP.
It is important to note that it isn’t necessarily Labour-leaning wards which will be hit the worst, but areas which are demographically Labour-leaning – ie poorer areas with minority ethnic communities, and high levels of rented and temporary accommodation. Ipsos MORI research supports this, finding that only 69% of BME voters are registered, and only 44% of 20-24 year olds (as opposed to 97% of 60-64 year olds).
In some wards in the UK, as little as 50% of the VAP are registered. This is highly likely to be even worse after the introduction of individual voter registration.

For further information about the mapping technology contact Gemma Hinksman / Graeme Buck, Camargue on 020 7636 7366 or /

Notes to editors

The 10% rule has been broken for islands not connected by a road bridge. These proposed constituencies are the Isle of Wight, Na h-Eileanan an Iar (Western Isles) and Orkney & Shetland.
VAP has been used for 2015 to focus on representation. Also, not all ward electorate count data is publicly available across the UK.
The analysis is focused on usually resident population projections for 2015 and students have not been double counted, as can happen in the electoral registers. The population data places most students at their place of study. The usually resident population includes residents from outside the UK, Commonwealth and the Republic of Ireland.
The analysis was undertaken using CACI's mapping and data software InSite. The software is used to automatically optimise geographical areas within set parameters. In this case CACI created constituency areas within national boundaries and where possible within former county boundaries and local authority areas. Wards were used as the building block for the creation of the constituencies. In order to give maximum flexibility in creating the areas, existing constituency boundaries were ignored.
Mark Harper MP was quoted in The Guardian on 12 August 2010

About ERS
The Electoral Reform Society is campaigning to change the way we choose our politicians. We believe that a fair voting system will improve our democracy, allow politicians to better represent you the voter and help them to tackle the serious issues facing our society.

About CACI
Headquartered in London, CACI Ltd is a wholly owned subsidiary of CACI International Inc., a publicly listed company on the NYSE with annual revenue in excess of US $3.15bn and employing approx 13,200 people worldwide.

CACI was founded in 1975 in the UK and operates from several offices across the country. We offer an unrivalled range of marketing solutions and information systems to local and central government and to businesses from most industry sectors.

CACI describes the nation.