Labour could lose 13 seats under boundary review: Changes to the political map may aid the Tories. Rosie Waterhouse reports Rosie Waterhouse considers the effects of planned boundary changes

Boundary Commission changes, which are currently re- drawing the parliamentary constituency map of Britain, could cost Labour between three and 13 seats in England alone, according to new research.

The losses would result in an increased majority for the Conservatives in the House of Commons of between seven and 26 at the next general election.

Roger Mortimore, a social studies researcher at Oxford University and an expert on Boundary Commission reviews, has conducted an analysis of the effects of the proposed changes.

The estimate of up to 13 Labour losses is lower than a previous prediction by the Tory party that Labour would lose at least 20 seats, which would translate into an increased Tory majority of 40. Now the Conservatives privately accept Mr Mortimore's estimates are more accurate but Labour disagrees with some of his findings.

David Gardner, Labour's national constitutional officer, argues the impact of the changes is still unpredictable and claims the outcome could range from a net Labour gain of four seats to a net loss of 17 seats.

Labour is anxious to appear optimistic, and so prevent the Tories from presenting the party as unelectable. But Mr Mortimore argues their figures for Labour gains are 'over optimistic'.

The Parliamentary Boundary Commission of England began its review of constituencies in 1991 and is expected to complete it by 1994, in time for the next general election. It will be the biggest shake-up of constituencies since the last review ended in 1983. The Boundary Commissions of Scotland and Wales are due to begin their reviews early next year.

Their aim is to apportion parliamentary seats according to a quota of roughly the same number of electors in each constituency. Since the last review, population shifts have caused the number of electors in English constituencies to range from 43,000 to 102,000.

In his report, Probable Political Effects of the Boundary Review in England, Mr Mortimore says: 'The direct political effects of the Boundary Commissions' decisions are inevitably unpredictable and only imprecise estimates are possible.'

The electorates of some counties and London boroughs are borderline and the number of seats allocated will depend on the extent to which the commissioners prefer to restrict any increase in the number of seats rather than strictly adhering to the rules governing electoral quota.

If the commissioners continue to respect London borough boundaries, London will be over- represented, partly because of a population drift out of the capital. If borough boundaries are respected it will lose between 7 and 11 seats - seven of them Tory and four Labour. However, if, as is more likely, the commission decides to 'pair' some boroughs and 'cross' boundaries, the number of seats would be reduced by as many as 13, just over half of them Tory.

The boundary review is expected to allocate 21 new seats in the shire counties, which are more likely to be won by the Conservatives. Labour argues they could also create new winnable seats for it if Tory voters from the suburbs were taken out of towns.

Mr Mortimore's survey concludes: 'In England as a whole the Tory majority may be increased by as much as 26 (the equivalent of gaining 13 seats) or as little as seven, (the equivalent of gaining three and a half seats) with the balance of probabilities tending towards a higher figure.'

The figures represent the range between the best possible scenario for the Tories - a net Conservative gain of 17 seats and Labour loss of nine seats - and the best scenario for Labour - a net Tory gain of five seats and a net loss of two Labour seats.

The commission has so far produced proposals for about half the constituencies in England. Once proposals are published public inquiries will be held if there are enough objections. Inquiries are due to be held shortly into the proposals for Bedfordshire, Leicestershire, Lincolnshire, Norfolk and Northamptonshire.

In another report, to be published next month, Mr Mortimore and Iain McLean, Professor of Politics at the University of Warwick, criticise the Boundary Commission's methods used to re-draw boundaries and 'apportion' parliamentary seats. In Apportionment and the Boundary Commission for England, they argue their paper 'shows that the outcome is defective . . . and that the defects lead to predictable biases of representation in favour of certain parts of the country'.

The commission is attacked for being inconsistent in apportioning seats, in some cases not allowing extra seats despite the larger than average electorate and in others creating more seats with fewer electors.

The report also criticises the commission for creating more seats, mainly in shire counties because of population drift, ignoring rules stating the number of constituencies should not continue to increase substantially. Scotland and Wales are already over-represented.

Non-Metropolitan counties

AVON No change or +1 seat

No change provisionally recomended; impact of extra seat unpredictable.

BEDFORDSHIRE +1 seat

Unpredictable political impact.

BERKSHIRE +1 seat

Probable Tory gain.

BUCKINGHAMSHIRE No change likely.

CAMBRIDGESHIRE +1 seat

Probable Tory gain.

CHESHIRE +1 seat

Unpredictable political impact.

CLEVELAND No change likely.

CORNWALL No change likely.

CUMBRIA No change likely.

DERBYSHIRE No change or

+1 seat

Impact of extra seat unpredictable.

DEVON No change likely.

DORSET +1 seat

Probable Tory gain.

DURHAM No change likely.

EAST SUSSEX No change likely.

ESSEX +1 seat

Probable Tory gain, at least in short term.

GLOUCESTERSHIRE +1 seat

Probable Tory gain.

HAMPSHIRE +2 seats

Probable 2 Tory gains.

HEREFORD & WORCESTER +1 seat

Probable Tory gain.

HUMBERSIDE +1 seat

Probable Tory gain.

ISLE OF WIGHT No change likely.

KENT +1 seat

Probable Tory gain.

LANCASHIRE No change or -1 seat

Extra seat awarded for special geographical considerations at last review may be retained; if withdrawn would be a Tory loss.

LEICESTERSHIRE +1 seat

Unpredictable political impact.

LINCOLNSHIRE +1 seat

Probable Tory gain. Labour may be helped in Lincoln.

NORFOLK No change or +1 seat

No change provisionally recomended. extra seat might help Labour in Norwich, otherwise a Tory gain.

NORTHAMPTONSHIRE No change likely.

NORTHUMBERLAND No change or -1 seat

Extra seat awarded for special geographical considerations at last review likely to be retained, otherwise probable Labour loss.

NORTH YORKSHIRE +1 seat

Tory gain.

NOTTINGHAMSHIRE No change likely.

OXFORDSHIRE No change likely.

SHROPSHIRE +1 seat

Probable Tory gain.

SOMERSET No change likely.

STAFFORDSHIRE +1 seat

Unpredictable impact.

SUFFOLK +1 seat

Probable Tory gain.

SURREY No change likely.

WARWICKSHIRE No change or +1 seat

Impact of extra seat unpredictable.

WEST SUSSEX +1 seat

Probable Tory gain.

WILTSHIRE +1 seat

Probable Tory gain, though may help Labour in Swindon.

METROPOLITAN COUNTIES

GREATER MANCHESTER -2 seats

One unpredictable loss in Manchester/Trafford (may be Lab seat

Manchester or Con held Davyhulme; one probable Tory loss Littleborough and Saddleworth.

MERSEYSIDE -1 seat

Lab loss.

SOUTH YORKSHIRE No change likely.

TYNE & WEAR No change likely.

WEST MIDLANDS -2 seats

Impact unpredictable, options too numerous.

WEST YORKSHIRE No change likely.

LONDON

If the Commission decides to respect London borough boundaries London will lose between 7 and 11 seats.

Virtually certain to lose one seat each:

BARNET Tory loss.

BROMLEY Tory loss.

CROYDON Probable Tory loss.

GREENWICH probable Tory loss.

KENSINGTON & CHELSEA Tory loss.

NEWHAM Lab loss.

WALTHAM FOREST Lab loss.

May lose a seat each:

BEXLEY Tory loss.

HAMMERSMITH & FULHAM Probable Lab loss.

KINGSTON Tory loss.

LAMBETH Lab loss.

If borough boundaries are not respected as some boroughs are paired and London is given only its correct allocation of seats 13 seats will be abolished. The overall result is far less predictable but the net effect may be fractionally more favourable to the Tories.