The last Saturday before polling day, a group around thirty female Sinn Fein campaigners, dressed in green waterproof jackets brandishing the party logo, are dashing door-to-door delivering leaflets through letterboxes. They are targeting voters in Ardoyne district in the Belfast North constituency, a working-class Sinn Fein stronghold, once at the heart of the troubles. 

The tempo is fast, spirits are high and there is an air of determination amongst the women. But they also know voters in these streets are already won over. 

The challenge is for Sinn Fein is to cross the religious and political divide to entice the electorate in loyalist areas of Belfast North, or undecided voters in more neutral areas of the constituency, to vote for them. 

Sinn Fein's candidate for Belfast North, John Finucane, believes Brexit may change minds. 

"Our futures are at stake in this election," says Finucane, who is also the current Mayor of Belfast. "It's an election which transcends party politics here in North Belfast and North Belfast has an opportunity on Dec 12^th not just to remove a Brexiteer, but the arch-Brexiteer."

Belfast North is one of three out of the four Belfast seats deemed to be marginal in the upcoming general election. Northern Ireland elects eighteen Members of Parliament to Westminster and Sinn Fein badly wants to snatch this seat from the incumbent Nigel Dodds.

 Dodds is a prize scalp for Sinn Fein. He's deputy leader of Democratic Unionist Party (DUP), and the party's leader in Westminster.

 Dodds has held  Belfast North since 2001, but his party is entering uncharted waters, backed into a corner by its conflicted pro-Brexit policy. 

Although the party backs Brexit, it is furious about Boris Johnson's deal, which proposes a border in the Irish sea. But it continues to support Brexit in principle. 

"Everyone is affected by the way in which the government and the opposition parties have failed to deliver on the referendum result in a timely and sensible way," Dodds said at a recent DUP campaign launch. 

"It's not Brexit itself, it's the way in which it has been conducted."

But the DUP is struggling to find support for this message in a constituency mostly voting to stay in the EU. Finucane wants to draw on the pro-Remain sentiment in the local electorate. 

"There's no such thing as a good Brexit," he says. " think Brexit in its truest form is incompatible with our Good Friday agreement, a peace agreement that we invested so much in and worked so hard for."

The DUP has played kingmaker in Parliament over Brexit and is aiming to hang on to all of the 10 seats it won in the last election. Pollster Bill White says the DUP could be less badly damaged by the issue of Brexit than first anticipated. 

"It hasn't really impacted their polling figures very much," he says. "People of a Unionist persuasion, they see the constitutional issue as key, even more important than Brexit."

Finucane is still upbeat that voters will shift in his favour. "They want change. There are problems in this constituency that need to be dealt with," he says. 

"We have a suicide crisis, a housing crisis, we've high levels of social deprivation and on top of that we have the fear that Brexit brings."

Belfast North  residents tend to vote along religious lines which are drawn firmly in the front lines of this key election background. The women out pounding the pavements to campaign for Sinn Fein are hoping for a seismic change to shift the boundaries which have held firm for decades.

A full list of candidates standing in Belfast North and Belfast South:

Belfast North

Nigel Dodds, DUP

John Finucane, Sinn Féin

Nuala McAllister, Alliance Party

Belfast South

Paula Bradshaw, Alliance Party

Claire Hanna, Social Democratic and Labour Party (SDLP)

Michael Henderson, UUP

Emma Little-Pengelly, DUP

Chris McHugh, Aontú