The Liberal Democrats, meeting in Bournemouth this week, believe they are on the verge of overtaking the Tories. Political Editor Graham Dines looks at the reality.

The Liberal Democrats, meeting in Bournemouth this week, believe they are on the verge of overtaking the Tories. Political Editor Graham Dines looks at the reality.

LOGIC and optimism do not go hand in hand. But that isn't stopping the Liberal Democrats believing they can at least treble their number of MPs in the East of England at the next election.

On the surface, it seems utterly ridiculous for the Lib Dems to claim they are about to supplant the ailing Conservatives as Britain's main opposition party.

But with the opinion polls showing them making steady advances, and with by-elections revealing the electorate's continuing dismissiveness of the Tories, Bournemouth this week has been awash with talk of the long awaited breakthrough.

The Liberal Democrats have had so many false dawns over the years that their opponents will write off the party's latest predictions as nothing more than conference hype. And one look at the electoral mathematics shows just how high is the mountain they have to climb.

The distorted nature of the first-past-the-post system of electing MPs gave Labour at the last election 412 seats with 10.724million votes and 40.68% of the total poll, the Tories had 166 seats on 8.375million votes and 31,7%, while the Lib Dems with 4.814million and 18.26% won just 52 seats.

Thus Labour formed a government with a massive majority having polled just two-fifths of the popular vote.

The latest opinion polls show Labour and the Tories in the mid 30% range with the Lib Dems somewhere in the 23-28% bracket.

Although the Tories remain in an utter mess and currently show no signs of revival, the Lib Dems are far short of being able to overtake the Conservatives in vote share.

Even if they did, it's unlikely they would end up with more MPs with the Tories because of the way votes are spread around the UK's 659 parliamentary constituencies.

An in-depth look at East Anglia shows the yawning chasm facing the Lib Dems. There are just two Lib Dem MPs our of a possible 37 in Essex, Suffolk, Norfolk and Cambridgeshire and none in the wider East of England of Bedfordshire and Hertfordshire.

Having won Colchester in 1997 and holding it in 2001, there was been no ripple effect in Suffolk and Essex. The party's only other gain was in North Norfolk in 2001, where Norman Lamb - now Charles Kennedy's Private Parliamentary Secretary - sneaked home

In Suffolk, the Lib Dems finished in third place in all seven constituencies, which returned five Conservative and two Labour MPs.

Yet the Lib Dems are master tacticians in the art of ruthlessly targeting seats. And they have identified seven possible gains which both Labour and the Tories would be well advised not to ignore.

Labour seats being eyed in the East of England are Watford, St Albans, Cambridge and Norwich South. The candidate in Watford is the redoubtable Sal Brinton - daughter of former ITN newsreader and one-time Tory MP Sir Tim Brinton - and even Labour privately concedes it would be remarkable if MP Claire Ward holds on next time.

In Cambridge, the student and academia radical vote, mobilised against the Iraq war and the future of tuition fees, could well see the defeat of MP Anne Campbell to the Lib Dems.

It seems improbable the Lib Dems could topple Education Secretary Charles Clarke in Norwich South, it doesn't stop them predicting they will pull off the shock of the General Election.

To do so, they have to count on the student vote in the University of East Anglia and convince the 10,551 people who backed the Tories last time that the only way to defeat to Mr Clarke is to vote Lib Dem.

Closer to home, there are three Tory held seats which will the subject of special attention from Charles Kennedy's party - Chelmsford West, Suffolk South and Norfolk South.

Down in Chelmsford West, the Lib Dems were pushed into third place for the first time in a generation. But the one great quality for which you have to admire the Lib Dems is their tenacity. They are in it for the long haul - candidates try, try and try again in the same area, unlike the seat hoppers of the Tories and Labour who, with only a few exceptions, tend to clear off to new pastures if they fail to win a constituency.

In Chelmsford West, the Lib Dems fell away in the 2001 General election, with their candidate Stephan Robinson suffering the double ignominy of dropping into third place behind the Tories and Labour and failing to win a county council seat on the same day.

Mr Robinson, who will again fight Chelmsford West, said: "There is no doubt the Lib Dems will at the very least push Labour into third place at the next election. Labour voters feel let down and are looking for a credible alternative. They do not see it in the Tory Party, which is all over the place and lurching to the extreme right.

"I believe we have an excellent chance of overhauling the Conservatives in Chelmsford West next time, but even if that does not happen, we will start as favourites in the new Chelmsford seat which has been created by the Boundary Commission.

"Labour is nowhere in the borough. It cannot possibly win the parliamentary seat and I am sure we can squeeze Labour's vote. Labour voters will come over to us if they can see a real possibility of ending Tory representation in this part of Essex.

"We will also be helped by a fractured Tory vote, with the UK Independence Party taking advantage of Conservative double speak on Britain's relations with the European Union."

Lib Dem campaigns in Chelmsford have been recognised at national level. The constituency party was shortlisted for the Penhaligon prize, given to the constituency party which has done most to further Lib Dem aims. In the past year, 111 new party members have been signed up in Chelmsford.

Over the border, Suffolk South will see an almighty effort to oust Tory Tim Yeo - even though the Lib Dems will not be choosing their candidate to fight the election until November.

Tory Tim Yeo took advantage of the divided opposition in the seat which includes Hadleigh, Long Melford, Sudbury, and Shotley to increase his majority in 2001. Labour finished in second place, but the Lib Dems believe they will build on rural discontent with Tony Blair's government to propel them into at least second place next time.

Perhaps the best bet in the east of the region is Norfolk South, where candidate Ian Mack has been campaigning for nearly two years. This largely rural seat, centred on Diss and Long Stratton, has always been in the sights of the Lib Dems, but although they control the district council level, the Tories have always been comfortably returned to Westminster.

Mr Mack says: "The Conservatives must realise Norfolk South can no longer be counted on as a certain win. If the Tories believe they can hold it by supporting hunt and rubbishing Europe, they are sadly mistaken."

For Colchester Lib Dem MP Bob Russell, all the indicators in the East of England point to at least a doubling of the number of Lib Dems MPs from the region. With a fair wind, he believes the figure could treble and he even holds out an even longer shot - that Bury St Edmunds, currently a Tory-Labour marginal, is not beyond his party if it keeps gaining in popularity.

"We have a Labour government which is Tory in all but name and a Conservative party which has moved so far to the right that millions of voters can no longer countenance supporting it," says Mr Russell.

"The only party fighting for social justice is the Lib Dems - the gaps between the haves and have nots has widened since Labour came to power and disillusioned Labour voters will help us give Tony Blair and Michael Howard a massive shock at the next election.

"If we continue to rise in the opinion polls, and come election time we are in the high 20% mark, then we will see throughout Britain, and especially our region, a Liberal Democrat party which can not longer be dismissed as the home of the protest voters."

But amid all this Liberal Democrat frenzy, I should issue a health warning, although I certainly think complacency in the Tory and Labour ranks would be highly dangerous.

The Lib Dems presume three factors that cannot - yet - be assumed:

That the Tories next year will still be seen as no-hopers, and that tens of thousands will switch to Kennedy's crew to defeat Labour.

That the UK Independence Party will attract Tories to their anti-EU banner in record numbers, letting the Lib Dems gain Conservative seats.

That Labour voters, many of whom would have voted for Margaret Thatcher in the 1980s, would rather now support the Liberal Democrats than return to the Tories in protest at the Blair government's policies.

None are the foregone conclusions that excited Liberal Democrat delegates in Bournemouth would have you believe.