On the campaign trail in Crewe

By Ben Wright
BBC News political correspondent

The election posters have started to sprout in the streets and fields of the Crewe and Nantwich constituency.

Crewe looks set to be a closely-fought contest

With campaigners, visiting party heavyweights and TV cameras clogging up Crewe it's obvious that the by-election circus has come to town.

Gwyneth Dunwoody, who died last month, was Crewe's Labour MP for 34 years.

This seat is synonymous with her name. She was so well-liked they even named a road after her - there is a bowling alley there.

The more rural, Conservative-leaning area around Nantwich was added to the seat in 1983.

At the last election Labour won with a majority of just over 7,000.

But now Mrs Dunwoody's daughter Tamsin has a real fight on her hands to keep the constituency Labour.

Full list of candidates

Canvassing in Crewe's town centre, she makes her pitch.

On the Crewe campaign trail

"My name carries a lot, of course it does. I'm a Dunwoody, I'm a fighter. But it's also about the local issues."

Considering the current gloom gripping the government, this seems a sensible strategy.

But her opponents want to keep the spotlight on national politics.

With the success of the local elections under their belt, Conservative strategists are quietly confident about their chances here.

Their local election tactician, Eric Pickles, is running the campaign from an old railway building near the station and the scrapped 10p tax rate is the cornerstone of their message.

"The 10p tax is hurting people here", says Edward Timpson, the Conservative candidate, who belongs to the famous family of shoe-repairers.

"The message needs to be sent to Gordon Brown that he hasn't got the answers, that he's not listening and there needs to be a change."

This could be a very big moment for the Tories. The party has not made a gain in a by-election since 1982.

'Labour collapse'

In recent years, the Liberal Democrats have made by-election upsets one of their specialities.

This is easily achievable for us to win Elizabeth Shelton Lib Dem candidate

The party is practiced at swinging into gear when the by-election whistle blows, mustering activists from around the country to help with the canvassing ground war.

They are starting here in third place and face the danger of being squeezed as Labour and the Conservatives slug it out.

But their candidate Elizabeth Shelton is confident. "The Labour vote has collapsed now," she says.

"People see the Conservatives as hypocritical. This is easily achievable for us to win."

Some by-elections come to define a political moment and this one could set the mood in Westminster for the next two years.

The government will hope the result in Crewe and Nantwich on 22 May is interpreted as renewal rather than ruin.