You'd think that with their annual conference opening the political season by the sea next week, the Lib Dems would have their eyes firmly focused on Brighton.

Not a bit of it. The party is pouring all its energy into an unlovely piece of London known as Brent East.

Here it is hoping Sarah Teather can do in tomorrow's by-election what Eric Lubbock achieved for the old Liberals back in the Sixties and cause shockwaves throughout politics.

The Hove-based activist hopes to snatch this normally solid seat from Labour in the same way as Liberals won the Orpington by-election back in the days when Harold Macmillan was Prime Minister.

She could find herself on Friday as the youngest MP in Britain.

Sarah Teather, 27, who began her political career in Hove, has fought a fierce campaign in the North West London seat which sees the party neck and neck with Labour in opinion polls.

Even Home Secretary David Blunkett has admitted Labour could lose.

Lib Dems leader Charles Kennedy, who has been to Brent several times, said: "It's a photo finish.

"But there really are signs that we can do it. Sarah is now on the national stage and could become the youngest MP."

Miss Teather lived in Wilbury Road, Hove, and was a member of the local Lib Dems while working as a research chemist.

Coun Paul Elgood, group leader on the city council, said: "Not long ago she was dropping leaflets through the letter box for me in Palmeira Square. Now she could be an MP."

If she wins - or at least converts a miserable third place at the General Election into a good second - the Lib Dems will have served notice on Labour that they are out to grab power next time.

Gone are the days when Paddy Ashdown cosied up to Tony Blair in the hope of power sharing or at least proportional representation.

Although the Lib Dems are still committed to PR, current leader Charles Kennedy is prepared to win seats from Labour on the first-past-the-post system.

For many years, Liberals prospered only when a tottering Tory regime was in power at Westminster. After the high hopes of Orpington, election progress waned when Harold Wilson took power and by 1970 you could once again, as the old joke had it, comfortably fit all its MPs into a phone box.

Paddy Ashdown achieved an astonishing feat in 1997 when, in the wake of a Labour landslide, he guided the Lib Dems to more than 50 seats, their highest total since the days of Lloyd George.

Charles Kennedy did no less well when four years later he managed to increase the numbers in another landslide.

Once the excitement of Brent East is over, party members will pour into Brighton this weekend in optimistic mood. Things are looking good.

While Tony Blair's star is waning, thanks to Iraq and cracks in the economy, Iain Duncan Smith and the Tories are not making much progress in the polls.

The Lib Dems are hovering around 20 per cent, above their usual mid term mark and they are faring much better than that in the elections that actually matter, for local council by-elections.

They are back in Brighton, one of their favourite venues, for the second year in succession.

Although their representation on the city council is small, the party spread from one to two wards at the local elections in May.

As party president Lord Dholakia will explain to anyone listening, Brighton is the resort where, about the time of Orpington, he achieved a famous local victory on the old county borough council in Pier ward.

The popular president will be making one of the keynote speeches along with other Lib Dem luminaries such as foreign affairs spokesman Menzies Campbell, a man who undoubtedly would have been a Minister by now had he hitched his wagon to one of the two major parties.

He will bring Iraq on to the platform at the Brighton Centre knowing it will be uncomfortable for Labour and a boost for the Lib Dems who took the distinctive line in Parliament of querying the war, unlike the Tories.

Finance spokesman Matthew Taylor, still too boyish-looking for his own good, will tweak the Chancellor's tail over the economy while Dr Evan Harris will speak on health.

They will give more details of the party's radical plans to slim down central government so that more money is free for vital services.

Sussex MEP Chris Huhne will be prominent in the preparations for next year's European Parliament elections in a debate on Monday.

Simon Hughes, will on Tuesday, make a speech as part of his campaign to oust Ken Livingstone as Mayor of London.

The conference kicks off on Monday with speeches by the deputy mayor of Brighton and Hove, David Watkins and Lewes MP Norman Baker.

Charles Kennedy not only answers questions live from party members on Monday but also delivers his conference speech in the hope of sending the troops home happy on Thursday.

The old Liberals were noted for chaotic party conferences characterised by a knack of attracting a lot of unattractive-looking men with beards and sandals.

Now it would be hard to distinguish your average Lib Dem delegate from one attending the other two party shindigs this year in Bournemouth and Blackpool.

But one legacy of the past remains - Lib Dems do seem to have more fun than the other parties.

Perhaps this has been because they have been so far away from power. But there won't be laughs if Charles Kennedy tells them, as David Steel did all those years ago, to go back to their constituencies and prepare for government.

With Labour and the Conservatives looking vulnerable, the Lib Dems look likely to progress, especially if tomorrow's Brent East by-election finds the other parties at the end of their Teather.