Tactical voters could hold the key

Tactical voting could seal the fate of dozens of marginal seats in London and the South-East.

Recent polls show how 30 per cent of the electorate have yet to make up their minds.

The parties fear people will use their vote tactically to teach Tony Blair a lesson over the Iraq war or to keep Michael Howard and the Tories in opposition.

The issue of tactical voting - traditionally seen as a Left-wing voting ploy - has become a central issue in the election with so many marginal seats across the country.

Once-loyal Labour supporters could use their vote to shrink the Government's majority and reduce the Prime Minister's power base from four years ago.

Labour fears it could be vulnerable from a last-minute backlash as less solid supporters drift back to the Liberal Democrats and Conservatives. And if disillusioned Labour supporters also fail to turn out or vote against the party, then Tony Blair's majority could be cut back substantially. Crucial seats in London and the South-East include Hammersmith and Fulham, Croydon Central and Bexleyheath & Crayford.

In all three constituencies, the result could be decided by how the Liberal Democrat supporters cast their vote.

Labour is reliant on Liberal Democrats who voted against the Conservatives in 2001 staying loyal.

But many Lib-Dems are unwilling to support Tony Blair this time round because they disagree so strongly over the war.

The Tories hope that if sufficient numbers vote with their conscience rather than to keep Michael Howard out of No 10, the Conservatives could eventually be the main winners.

Other Labour-held seats which could be decided by the public using tactical voting include Enfield North, Finchley & Golders Green and Putney.

Again, Labour is vulnerable from the combinat ion of disaffected supporters abstaining and Liberal Democrats refusing to join battle against the Tories.

The Lib-Dems are also banking on tactical voting to help them to victory in the Conservative-held seats of Orpington and Maidenhead.

Both these constituencies are vulnerable if sufficient numbers of Labour voters switch to the Lib-Dems.

Liberal Democrat strategists are hoping that the prospect of ousting shadow minister Theresa May in Maidenhead will attract Labour voters who would not normally turn out to back Charles Kennedy's party.

Mr Kennedy is also relying on Labour support to fend off Conservative challenges to the Liberal Democrat marginals of Richmond Park and Sutton and Cheam. Here Labour holds the balance of power.

Outside the capital, Labour is engaged in a hard-fought battle to hold the Thames-side seats of Medway, Sittingbourne and Sheppey and Gillingham. All three could fall to the Conservatives if the Liberal Democrats turn their back on Labour.

However, Conservative insiders believe the effect of tactical voting can be over-estimated. They claim the strength of a local campaign and the personality of the candidate will be just as crucial in deciding the outcome.