Lib Dems could be the death of the Tories

This party has it in its power to prevent the Tories ever returning to office

There is an infectious spring in the step of Liberal Democrats in Bournemouth, which should worry both the other main parties. This is my seventh Liberal Democrat conference. Each one becomes a little harder to cover. Once it was possible to enjoy the dotty resolutions and minor rows that they sparked between the membership and the platform. The week used to be a pleasant curtain raiser before the subsequent oppressive security of the Labour and Tory conferences.

There is an infectious spring in the step of Liberal Democrats in Bournemouth, which should worry both the other main parties. This is my seventh Liberal Democrat conference. Each one becomes a little harder to cover. Once it was possible to enjoy the dotty resolutions and minor rows that they sparked between the membership and the platform. The week used to be a pleasant curtain raiser before the subsequent oppressive security of the Labour and Tory conferences.

Not this time. The press room is unusually crowded and hacks are spoilt for choice as to which fringe meetings to cover. There is hardly a beard or open-toed sandal in sight. It used to be easy to get into the hall with a minimum of fuss, and a conference pass was almost an optional extra. Now, police guard the entrances and full security checks take place.

The bars are crowded and the 1,800 or so delegates threaten to rival the size of the Tory attendance here, in the same hall, in a fortnight. While nearly every Lib Dem MP has come for the whole week, it is difficult to find many Tory MPs who will stay for more than one night - or even at all. Try as I may not to take it all too seriously, the Lib Dems' electoral possibilities really are beginning to scare me.

Vince Cable, the Treasury spokesman, has forced an iron discipline on the rest of his colleagues. Whether his figures add up is still open to question, but his bank manager style and previous business experience give him the same credibility on economic affairs that his colleague, Sir Menzies Campbell, established several years ago on foreign affairs. These two heavyweights are every bit the equal to their opposite numbers in the Tory Party, Oliver Letwin and Michael Ancram. And while Mr Cable does not yet pack the same punch as Gordon Brown, Sir Menzies is more than a match for Jack Straw.

But it is the front bench "Young Turks", David Laws and Mark Oaten, who should scare witless any Tory equivalent, such as David Cameron or George Osborne, recently promoted by Michael Howard. And while their Orange Book, which tilts towards acceptance of the free market, has caused ripples, the publicity surrounding these proposals has underlined the hunger of the new generation of Lib Dem MPs to be more than third-party frontbench spokesmen.

Talk of a Liberal Democrat government may be regarded by most hacks as far fetched, and the staging post of overtaking the Tories still looks a tall order, but this week has convinced me that this party has it in its power to prevent the Tories ever returning to office. The evidence on the ground suggests that the Lib Dems have put down deep tap-roots in to nearly all the constituencies they won from the Tories in 1997 and which they successfully held in 2001. The chances of any of these being won back by the Tories at the general election in 2005 - or indeed ever - are virtually nil.

Driving down the M3 from London to Bournemouth illustrates this graphically. Motorway signs point to Guildford, Winchester, Eastleigh and Romsey - all now Lib Dem constituencies. In the past, every one of these, even on a bad election day such as the Labour landslide of 1966, was a Tory shoe-in. Add the near total withdrawal of the Tories from Scotland and Wales, where about 25 seats were once automatically in the Tory column, and the Conservatives now have to look for about 50 seats elsewhere to replenish these permanently lost constituencies. And that is before any battle begins to win back Labour marginals.

But where are these alternative 50 seats? They simply do not exist. Where once they held a minimum of a couple of seats in most large cities - Sheffield, Leeds, Birmingham, Bristol and even Liverpool - the Tory tent there has also folded. If there is a challenge in either the wealthier middle-class outskirts of these cities or even in the rundown inner cities themselves, it is invariably the Lib Dems who are the principal alternative to Labour.

The Tory hope hitherto has beenpredicated on the basis that the Lib Dems required a huge national effort to target and then defend particular constituencies. The more seats they gained, the more mutual aid they needed to divert in order to cling on at a subsequent general election. This is no longer the case. Lib Dems are now succeeding in getting elected and re-elected by utilising support and effort solely within these constituencies.

There has been a determined attempt to convince sceptical commentators that the Lib Dems will abandon the sleight of hand which previously allowed them to get away with sending contradictory messages to voters, depending on whether the party was challenging in a Tory or a Labour-held constituency. Mr Oaten was at great pains, at The Independent fringe meeting, to pledge that the party would present the same message to voters in Winchester as in Watford (a target Labour seat). But it will still be Tory seats such as those held by David Davis, Theresa May and Oliver Letwin that provide the Lib Dems with their juiciest opportunities to capitalise on the current poll ratings. If the Tories die, it will be down to the Lib Dems.

mrbrown@pimlico.freeserve.co.uk