The first rule of campaigning in Edgbaston is to watch your step. Treading on the wrong piece of pavement could spell disaster, according to Labour's Gisela Stuart.

It's a sunny April day in Harborne High Street and Gisela is out schmoozing the voters. She and her team take care to stay close to the road, as the pavement there belongs to the city council.

Stand too close to the shops and you're on pathway owned by the local traders, apparently. And they don't approve.

Rival candidates have been known to stray into the forbidden zone, only to be moved along by disgruntled retailers. But it's a mistake the Labour team are far too slick to make.

Edgbaston is the ultimate key marginal in this election. When it fell to Labour on election night 1997, the scale of Tony Blair's victory became clear. And it's a seat Michael Howard's Conservatives need to win this time, if they are to form a Government.

Ms Stuart saw off the Conservative challenge with relative ease in 2001, increasing her share of the vote slightly.

But with a majority of just 4,698, it's hardly safe. And the Conservatives made a tactical error last time, putting up a male candidate when Edgbaston has been represented by a woman for 50 years.

They've learned from their mistakes, and this time their hopeful is Deidre Alden, a children's illustrator and local councillor. The election has certainly stirred up interest. As Ms Stuart arrives at her pitch, opposite WH Smith, she is immediately approached by a young man with a determined look on his face.

He reaches out and grabs her hand, offers a no-nonsense "good luck", and heads immediately off again. That's one in the bag. Far from avoiding this political roadshow, shoppers are keen to chat. At one point Ms Stuart's small team of helpers have to organise a small queue, so keen are voters to quiz their candidate.

One asks about Birmingham's postal voting scandal, which Ms Stuart later tells me has become a hot issue in the election. A young man wants to know what Labour is going to do about modern apprenticeships.

And a middle aged woman asks: "Is anything ever going to be done to stop the thugs getting away with it?" This is grist to the mill for Ms Stuart, who talks about ASBOs, curfews and Labour's plethora of measures to tame yobs.

Meeting shoppers may not directly win many votes, but it's all about making the election exciting, says Ms Stuart.

"It creates a sense of occasion, and lets everyone know an election is taking place. And if they don't see me out campaigning, they tell me off. People expect me to work for their votes, not take them for granted."

I leave her to her toil and head to Harborne School for Girls, where Coun Alden is encouraging students taking part in a mock General Election, organised by BBC's Newsround.

The pupils involved are 15 years old and, of course, cannot vote in the real thing. But it's important to encourage the next generation to become interested in politics, Coun Alden tells me, and in any case it's only a short break from her relentless door-knocking.

Nobody could miss the fact that an election is taking place here. The walls are plastered with posters put up by youngsters representing the three main parties in the schoolyard ballot.

The Conservative candidate has a particularly hard-hitting message. It reads: "Under a Labour Government, a gun crime is committed every hour! If you don't want to get shot, vote Conservative!" I don't want to get shot, so it certainly gets me thinking. But this is the pupil's view, which goes a little further than the official Tory line. What is the real candidate saying?

I find Coun Alden being quizzed by budding reporters from the school newspaper. "It seems that, in the end, we actually went to war on a lie," she is telling them. Clearly, we are discussing Iraq.

"I can never forgive Tony Blair," she continues. "To my mind it is despicable."

Pretty strong stuff, but there's no holds barred here. The young reporters are more fearless than Paxman.

Aren't the Tories racist, asks one? No way, says Coun Alden, citing Disraeli as the first ethnic minority Prime Minister.

And then her student counterpart speaks up. Dee Shen, aged 15 and wearing a blue rosette with pride, tells her friends the Tories have more ethnic minority candidates than any other party.

And she knows her stuff. How can Conservatives improve public services without raising taxes? "£57 per second is wasted on Labour's health bureaucrats," says Dee.

And what about MRSA? "That is just another area in which Tony Blair has let British people down. Every year 5,000 people die from infections picked up in hospital."

Memo to Michael Howard: snap her up quick. This girl doesn't need A-levels.

Outside the school gates, the campaign becomes less stressful. Coun Alden takes me knocking on doors, and I would like to report there was much excitement - but every householder we met simply confirmed they would be voting Conservative, and that was that.

But are these typical voters? The most Coun Alden will say is that she is "hopeful" of winning the seat.

The only thing that's certain is that all eyes will once again be on Edgbaston on May 5.