Constituency profile: Brighton Pavilion

Energetic, engaged, with her media savvy manner and distinctive cropped hairstyle, Ms Lucas has made a strong impression in her five years at Westminster.

Thoughtful and considered in the Commons chamber, she can also be radical.

She has been arrested at a protest against fracking and also told to cover up a T-shirt displaying the slogan "No More Page Three" in large lettering during a Commons debate.

But things have not gone so well on her home turf.

There has been criticism at times of the Green-run council, occasionally, and rather damagingly, from senior Green party members themselves.

Ms Lucas, who stood down as her party leader around halfway through the last parliament, is in a battle to save her seat and with it, although the Greens would deny it, potentially her party's only representation in Parliament.

The key fight is between the party and Labour's Purna Sen.

Labour held the seat between 1997 and 2010 and the Labour candidate is seen as the perfect person to take on Lucas, with a strong campaigning track record and interest in equality and international issues.

Outside the Friends meeting house in the town centre, where an election hustings is due to take place later, many voters say that they are still to make up their minds who they will back come May 7.

Those who are Green supporters are, often, fervently so.

"I would not like to live in a constituency that was not represented by a Green MP," Abigail Smith, a retired nurse who puts her age at 70-something, says.

"I don't see what the other parties are doing about the biggest issue we face, the environment."

But others are keen to see the battle in more national terms.

"I'm voting Labour, though I have not been telling Green campaigners that," says student John O'Neill. "This is not just about Brighton".

One of the main questions - as with many other seats at Westminster - is where will the Lib Dem vote go?

The party came fourth his last time around and picked up thousands of votes.

However, support nationally for the Lib Dems has fallen dramatically since the party's decision to enter into coalition with the Tories in 2010, and the party is expected to be punished at the ballot box heavily in Brighton.

Another question is what impact will Ukip make?

The party is not forecast to do well in a constituency where a quiet residential street contains the bright royal blue painted 'Private Shop', advertised as Brighton's first licensed adult boutique, and another store front offers "original funerals".

But Nigel Farage's party is expected to pick up votes all the same.

Down by the beach, beside the huge Brighton Wheel and the pier blaring out a song declaring the singer is "Ready for Love" one Ukip voter, who declined to be named, said that the party would get his backing and predicted there it would be supported by many others in the area as well.

He added: "It might not happen in Brighton, but Ukip are going to cause a revolution in this general election".

In a seat where many can say who their MP is, some are trying to turn Ms Lucas' perceived popularity against her.

The Conservatives are campaigning that the seat deserves more than a "lone vote of protest" MP, and attacking what it has denounced as the "naive" local council, both accusations furiously denied by the Greens.

Tory peer Lord Ashcroft has carried out two constituency polls in the seat.

The first, last summer, suggested that Labour and the Greens were neck-and-neck in terms of voting intentions.

The second, in December, so still some four or so months ago, suggested that the Greens were ten points ahead.

Both were before the Green 'surge' triggered when the party was initially excluded from the televised leaders' debates.

But they were also carried out before recent criticism of the performance of Green leader Natalie Bennett and intense questioning about how the party plans to pay for some of its policy pledges.

On the streets of Brighton, ordinary voters do not seem very sure about what will happen in May.

One young man tells a group of Green canvassers that he is not going to vote for Lucas although he thinks that she has "done a lot of good" for the area.

He won't be drawn on his reasons but offers them an assessment of their campaign so far: "I think a lot of work needs to be done."