The Newtownards Road that connects east Belfast to the city centre is a rather nondescript artery of houses, shops and offices until you come to CS Lewis Square.

Named after The Chronicles of Narnia author who grew up nearby, the square has bronze sculptures featuring characters from his story The Lion, the Witch and the Wardrobe, with the latter a portal to a realm frozen in a hundred-year winter.

Beyond the square, heading into town, the road changes. Union flags sprout from lampposts and large murals adorn walls. Some celebrate George Best and the workers who built the Titanic at the Harland & Wolff shipyard. Others depict first world war soldiers.

Facebook Twitter Pinterest A man walks his dogs in CS Lewis Square, which commemorates the Chronicles of Narnia author. Photograph: Paul McErlane/The Guardian

Most commemorate the Troubles and feature images of people murdered by the IRA, as well as the loyalist paramilitaries who purported to avenge them. A new one, on Belvoir Street, shows two Ulster Volunteer Force figures with balaclavas and rifles flanking an exhortation, or threat: “The prevention of the erosion of our identity is now our priority.”

The mural appeared in recent days but the sentiment harks back to Northern Ireland’s foundation in 1922 as a state for people who wanted to remain British, a resolution frozen in place a century later.

“You always get that impression, every election, that your heritage, your country, is under threat,” says John Davidson, 77, a former shipyard welder who has served for 50 years as treasurer of the Harland & Wolff Welders football and social club.

For working-class loyalists, the 12 December vote will be no different, he says. “They have one eye on Brexit because they want to stay in the union. At the minute, none of us know exactly how it is going to pan out.”

Facebook Twitter Pinterest An Ulster Volunteer Force mural on Belvoir Street. Photograph: Paul McErlane/The Guardian

Northern Ireland has pressing problems. The power-sharing assembly at Stormont is defunct, leaving a political vacuum. Health services are in crisis, with doctors scaling back hours and nurses voting to strike. Untreated mental health problems have produced high suicide rates.

Yet Davidson and others in the East Belfast constituency interviewed for this article agree the election is about Brexit and by extension Northern Ireland’s position in the UK. Constitutional uncertainty freezes out all other issues.

The Narnia analogy has limits. Davidson, for instance, speaks warmly about his Irishness. He cheers the all-Ireland rugby team and enjoys visiting the Republic of Ireland. “No hangups whatsoever. People cross the border easily – Dublin, Donegal for a weekend. I’m as proud to be Irish as I am to be part of the UK. You can’t deny it, you are what you are.”

A sense of Britishness, however, trumps everything. It contributed to Davidson’s vote to leave the EU in the 2016 referendum. There was too much Euro-meddling, too many immigrants, he says.

Davidson – who wants to secure Brexit and the union – will vote for the Democratic Unionist Party’s Gavin Robinson who is hoping to be re-elected. The DUP supported Brexit but vehemently rejects Boris Johnson’s deal, saying it will weaken the union by creating a border down the Irish Sea. Davidson shrugs off any contradictions. “I’m an optimist.”

Facebook Twitter Pinterest ‘None of us know exactly how it is going to pan out,’ says John Davidson, treasurer of Harland & Wolff Welder’s club. Photograph: Paul McErlane/The Guardian

Others here share the bleakness of a new poster up the road that is already peeling in the chill wind: “Resist the betrayal act,” it says, over an image of the prime minister. “Ulster says no to an economic united Ireland.”

Jim, a loyalist in his 60s who withholds his surname, grimaces at mention of the deal. “People here won’t stand for it. There’ll be riots.” The former labourer does not want to cancel Brexit, saying that would be a win for Sinn Féin and the IRA. Even worse than Johnson’s “backstab” deal would be Jeremy Corbyn winning the election and allying with Republicans, he says.

Brexit, in other words, has become a trap. Jim blames a pan-nationalist conspiracy, Tory duplicity and ungrateful English, Welsh and Scottish people who, according to an opinion poll this week, are willing to lose Northern Ireland in order to obtain their preferred Brexit outcome. “We’re only British when they need us,” says Jim.

He has no great ardour for the DUP but hopes the party will return to Westminster in force to sort out the mess.

Interviews with loyalists aged from 18 to 80 yield recurring views: the DUP bungled Brexit and its opposition to marriage equality and abortion rights is “daft” and “embarrassing” but the party remains the union’s best guarantor. A front page headline in the Purple Standard, a loyalist magazine, boiled it all down: “It’s the constitution, stupid!”

On the other side of CS Lewis Square, heading east away from the city centre, flags and murals vanish and the houses grow bigger and fancier. This is the realm of East Belfast’s “soft” unionists and non-aligned voters. Many voted remain.

A callout to Guardian readers elicited dozens of responses from Ballyhackamore, Belmont and other suburbs. They expressed concern about health services, schooling, the environment, paramilitary activity and the lack of devolved government but regarded Brexit polarisation as a key election issue.

“Brexit has opened Pandora’s Box re: Good Friday agreement and the union,” said a school governor. A 50-year-old architect wrote: “Attitudes have hardened – the two communities are split by the sectarian divide.” Both, like most respondents, requested anonymity, reflecting skittishness about speaking out.

Naomi Long, the leader of the cross-community Alliance party, is running in East Belfast. In an interview at her home Long says Brexit has fanned debate about a united Ireland. “You have a real challenge to the integrity of the UK.” The tone is rueful, exasperated.

Long, 47, advocates a liberal, non-sectarian Northern Ireland that remains in the EU. She accuses the DUP and Sinn Féin of channelling Brexit into traditional tribalism. “I’m not at all surprised it’s become an Orange/Green tussle. It so binary. It’s a very difficult time to feel hopeful in politics.”

Long was MP for East Belfast from 2010-15. She lost the seat to Robinson, who did not respond to interview requests, after loyalists accused the Alliance party of backing Republicans in a dispute over flags.

Long’s uphill attempt to wrest back the seat will test Alliance’s viability as a third force. The middle ground of “neithers” is surprisingly populous – 50% of people identify as being neither unionist nor nationalist – but in elections most back unionist or nationalist parties.

Sinn Féin to stand aside for remain candidates in three constituencies Read more

That may be changing. In May’s European elections Alliance and other non-aligned parties took 21% of the vote, their highest share since the 1960s. Long was elected an MEP, taking a seat traditionally held by the Ulster Unionist party (UUP).

Alliance is shunning electoral pacts but under a pro-remain banner Sinn Féin, the SDLP and Greens are standing aside in East Belfast to help Long. That may backfire. Many view pro-remain pacts here and and in other constituencies as a thinly veiled pan-nationalist accord, one mirrored in North Belfast where the UUP is standing aside to help the DUP’s Nigel Dodds.

Facebook Twitter Pinterest Alliance party supporters Delphine McCourt and her husband Robert say they plan to sail away one day and leave Northern Ireland for good. Photograph: Paul McErlane/The Guardian

Robert McCourt, 66, an Alliance supporter, fears Northern Ireland is adrift. “It would be nice to have hope but then you see the antics of the DUP – they defended the referendum when people here voted to stay in Europe,” he said.

McCourt comes from a protestant background and was in the same class as Sammy Wilson, the DUP MP and Brexit spokesman. McCourt took a different path, becoming a chartered engineer, working abroad and embracing Irishness more than Britishness.

Though a remainer, and no fan of Johnson, McCourt considers the prime minister’s deal economically sensible, echoing many business owners who fear the alternative is a no-deal Brexit. “I think it’s wonderful, the way to go,” he says.

McCourt likes to think “dinosaurs” such as him will make way for a new generation that will reinvent Northern Ireland. But he worries Brexit is poking at the Troubles’ tangled legacy. “The wounds are still there. It wouldn’t take much to open them up again.”

His French Canadian wife Delphine, 44, agrees. “Here you sense there is still a lot of anger and sadness. If this place could only put aside its divisions – the people are powerhouses.”

The couple plan one day to board their boat, an 11-metre cutter, and sail away for good to somewhere south, somewhere warm.