Even without Tory revival, Blair can lose out

Tony Blair could be denied an overall majority at the next general election by a Liberal Democrat advance that enables the Tories to capture more than 70 Labour-held marginal seats without winning a greater share of the national vote.

Tony Blair could be denied an overall majority at the next general election by a Liberal Democrat advance that enables the Tories to capture more than 70 Labour-held marginal seats without winning a greater share of the national vote.

A study for The Independent suggests that Michael Howard could achieve a hung parliament without improving the Tories' poor performance in 2001 if people disenchanted with Mr Blair and opponents of the Iraq war vote tactically against Labour in the election expected next May.

The study by John Curtice, professor of politics at Strathclyde University, provides a warning to Labour that it cannot take the next election for granted even though recent opinion polls point to a 100-strong majority for Mr Blair. Labour strategists are worried that a "Lib Dem effect" could cost the party scores of seats, especially if problems in Iraq remain at election time.

Officials in the three main parties believe that the tactical voting against the Tories that helped Labour to win in 1997 and 2001 will disappear next year.

Professor Curtice calculated that an 8.5 per cent national swing from Labour to Mr Kennedy's party and an end to previous tactical voting could result in a hung parliament even if the Tories stand still. The Tories would gain 71 seats from Labour without winning a higher share of the vote, while losing 13 to the Liberal Democrats. Labour would lose 71 constituencies to the Tories, 12 to the Liberal Democrats and one each to the Scottish and Welsh nationalists.

The Liberal Democrats would not reap huge rewards because of Britain's electoral system. Instead, the Tories would overtake Labour in Labour-held marginals, while Mr Kennedy's party gained 12 seats from Labour and 13 seats from the Tories, including those held by the shadow ministers David Davis, Oliver Letwin, Theresa May and Tim Collins.

On this scenario, Labour would have 328 seats and 31.8 per cent of the vote, the Tories 224 seats (32.7 per cent) and the Liberal Democrats 77 seats (29 per cent). That would leave Mr Blair two seats short of an overall majority.

Recent polls giving Labour a three-point lead over the Tories would give Mr Blair a majority of 109. Even without a Liberal Democrat advance, Professor Curtice calculated that the absence of the tactical voting could reduce Mr Blair's majority to 75. When the new Scottish constituencies are included, the majority falls to 58, which would leave Mr Blair heavily dependent on left-wing Labour MPs.

Professor Curtice found that the "Lib Dem effect" means the Tories need a smaller than expected lead over Labour to prevent a third Blair victory. On a uniform swing, the Tories need to be 3.7 points ahead of Labour before Labour loses its overall majority. Without tactical voting, Mr Howard's party would need only a 2.1 point lead to achieve a hung parliament.

Peter Hain, the Leader of the Commons, said the study showed the dangers of Labour supporters "having a punt on the Liberal Democrats in the mistaken belief that the election will be a cakewalk for us.They would be horrified if they voted to give us a bloody nose but actually elected a Tory MP and possibly even handed Michael Howard a back-door key to Number 10. In key Labour-Tory marginals, this shows that a Labour vote for the Liberal Democrats lets the Tories in."

Labour's private polling estimates that some three million of its natural supporters may back the Liberal Democrats or abstain in a protest over Iraq.

THE CONSTITUENCIES UNDER THREAT

If there is an 8.5 per cent swing from Labour to the Liberal Democrats and no tactical voting against the Tories, the following seat changes would occur.

Conservative to Liberal Democrat

Taunton; Orpington; Surrey South West; Dorset West; Haltemprice and Howden; Isle of Wight; Eastbourne; Wells; Westmorland and Lonsdale; Totnes; Wiltshire North; Maidenhead; Dorset North

Labour to Conservative

Dorset South; Braintree; Monmouth; Lancaster and Wyre; Kettering; Northampton South; Welwyn Hatfield; Shipley; Clwyd West; Bexleyheath and Crayford; Milton Keynes North East; Hornchurch; Selby; Edinburgh Pentlands; Hammersmith and Fulham; Thanet South; Forest of Dean; Wellingborough; Ilford North; Rugby and Kenilworth; Gillingham; Harwich; Enfield North; Calder Valley; Ayr; Redditch; Peterborough; Shrewsbury and Atcham; Dartford; Scarborough and Whitby; Hove; Preseli Pembrokeshire; Gloucester; Putney; Hemel Hempstead; Ribble South; Finchley and Golders Green; Wolverhampton South West; The Wrekin; Croydon Central; Elmet; Wimbledon; Stroud; Keighley; Sittingbourne and Sheppey; High Peak; Stourbridge; Brigg and Goole; Medway; Wirral West; St Albans; Vale of Glamorgan; Burton; Hastings and Rye; Bradford West; Chatham and Aylesford; Warwick and Leamington; Gravesham; Great Yarmouth; Wansdyke; Stafford; Tamworth; Dover; Watford; Broxtowe; Birmingham Edgbaston; Brighton Kemptown; Gedling; Harrow West; Enfield Southgate; Portsmouth North

Labour to Lib Dem

Falmouth and Cambourne; Colne Valley; Leeds North West; Reading East; Cardiff Central; Oldham East and Saddleworth; Bristol West; Birmingham Yardley; Aberdeen South; Rochdale; Edinburgh South; Inverness East, Nairn and Lochaber

Labour to Plaid Cymru Ynys Mon

Labour to SNP

Western Isles

Source: John Curtice, Strathclyde University