The pennine region: Campaigners seeking a welcome in the hillsides as they focus on valleys

Long before Gordon Brown finally named May 6 as polling day, for around three years in fact, the Conservatives have been working here as if engaged in a full-scale election campaign, desperate to secure the tiny 1.8 per cent swing needed to win the Pennines seat.

Add in a bit of glitz, in the form of Labour candidate Steph Booth, stepmother of Cherie Blair, and it has all the ingredients for an epic battle in a stunning setting which lends itself to a captivating drama.

Yet take a stroll around Hebden Bridge market and there is little sense of enthusiasm for the election in a constituency where Labour's 6,000-plus majority of 1997 has been whittled down to little over 1,000. Turnout in the Calder Valley fell from 82 per cent in 1992 to 67 per cent at the last election, and there are signs the trend may be continuing.

"Gordon Brown just wants to stay in power," says one trader. "What I think of his character I don't know – he seems a bit iffy to me. Cameron doesn't seem much better.

"Last time I voted because at the time I thought Gordon Brown was doing a reasonable job of the economy, but I think I might vote Lib Dem this time."

Wandering around town, two issues come up again and again – immigration and MPs' expenses. Another trader says "there's just too much immigration" although is keen to say they are not racist, and another says they will vote BNP – if at all – because "there isn't enough in the trough for the current lot".

While Ms Booth is keen to talk up Labour's chances – she reports support hardening since the turn of the year – Labour's campaign has been beset by trouble. The party has been split since Janet Oosthyusen was sacked as candidate, following Chris McCafferty's decision to stand down after 13 years as MP, and Ms Booth has been forced to deny allegations she attempted to discredit Ms Oosthyusen.

Conservative candidate Craig Whittaker, seeking to emulate Donald Thompson, Tory MP from the seat's creation in 1983 until he was wiped away in Labour's 1997 landslide, has had his difficulties too. As the Calderdale councillor in charge of children's services he has faced calls to resign, not least from opponents, over a damning report into failings at the department.

In a campaign which has got nasty at times he also claims to have been the victim of unfounded slurs and attacks on websites for which Labour sympathisers are suspected, but insists he wants to fight a clean campaign based on addressing key issues of crime, the economy and immigration.

With such a slim Labour majority, if Mr Whittaker can keep the Tory vote stable it will probably be enough to win the seat as Labour, although Liberal Democrat Hilary Myers, who has a 10,000 vote gap to plug, hopes to benefit from rising support for Nick Clegg, and the Greens will also attract some support.

Entrepreneur Jason Elliott says the Conservatives are "odds on favourites" but that turnout may be low.

"I think many people will stay away because of what has happened and the conduct of the campaign thus far," he says. "A lot of people won't vote and I imagine the turnout may be relatively low."

Head further south and the barrier between Yorkshire and Lancashire turns from Calder Valley into Colne Valley, the landscape just as dramatic and the Labour majority just as slim – this time estimated at 1,267 if the 2005 campaign had been fought on the new boundaries.

Largely rural, Last of the Summer Wine's home town of Holmfirth is the focus of the constituency where Tory Jason McCartney, still recognised as a former ITV Calendar presenter, has been working for three years to secure victory. David Cameron even held one of his town hall-style "Cameron Direct" meetings there recently.

The Tories remain confident of victory, but this is also a seat with a Liberal tradition – Richard Wainwright was the last Liberal MP to hold it as recently as 1987 – which means the success of Lib Dem candidate Nicola Turner will now become a test of whether Nick Clegg's leadership surge is a fad or has changed politics for good.

Labour's Debbie Abrahams, a health adviser, however, is attempting to stop that happening with a direct plea to Lib Dem voters on her website to back her and stop Mr Cameron getting into power.

Mr McCartney says everyone on the doorstep is at least willing to listen and engage, in itself a significant step forward for the Tories given their lowly plight in Yorkshire in recent years, while immigration and pensions are the big issues on the doorstep.

Embracing the internet as a campaigning tool – such as fighting to reinstate maternity services at Huddersfield Royal Infirmary – he is also striving to tap into the student vote which could help secure the Tories this vital seat.

The facts

Calder Valley

n Current MP: Christine McCafferty, Labour (Standing down)

n Notional majority*: 1,303

n Last election: Swing 1.8% Lab to Cons

Confirmed candidates:

n Conservative - Craig Whittaker

n Labour - Steph Booth

n Liberal Democrat - Hilary Myers

n BNP - John Derek Gregory

n English Democrat - Paul Rogan

n Green - Kate Sweeny

n Independent - Tim Cole

n Independent - Barry Greenwood

n UKIP - Greg Burrows

Rating: Must-win for the Tories

A-Z of Yorkshire constituencies

A run-through of the constituencies not covered in our tour of the battlegrounds:

Doncaster

Central

n Currently held by: Labour

n Current MP: Rosie Winterton

n Notional majority*: 10,325

n Last election: Swing 8.8% Lab to Lib Dem

Confirmed candidates:

n Conservative - Gareth Davies

n Labour - Rosie Winterton

n Liberal Democrat - Patrick Wilson

n BNP - John Bettney

Doncaster North

n Currently held by: Labour

n Current MP: Ed Miliband

n Notional majority*: 12,027

n Last election: Swing 4.2% Lab to Cons

Confirmed candidates:

n Conservative - Sophie Brodie

n English Democrat - Wayne Crawshaw

n Labour - Ed Miliband

East Yorkshire

n Currently held by: Conservatives

n Current MP: Greg Knight

n Notional Majority*: 6,284

n Last election: Swing 1.2% Lab to Cons

Confirmed candidates:

n Conservative - Greg Knight

n Labour - Paul Rounding

n Liberal Democrat - Robert Adamson