It was 9am on 24 June 2016. Peter Mandelson stood shellshocked on College Green in Westminster as Britain woke to its decision to leave the EU. It was, he told the television cameras, the worst day in British postwar history.

It did not feel like that 270 miles north, in Mandelson’s former constituency. For drinkers in Hartlepool’s Cosmopolitan pub, it felt like Britain’s independence day. “They were cheering and carrying on all day,” says the landlord, Tim Fleming, a Ukip councillor. “There was a state of shock because most didn’t believe they were going to win.”

The beer-soaked delirium in Hartlepool, whose resounding 69.6% vote for Brexit was the highest in the north-east, was in sharp contrast to the despair of its former MP. An arch-Europhile, Mandelson now appears the antithesis of the coastal town he represented in parliament for more than a decade.

It may be 13 years since the Labour peer, now Baron Mandelson of Foy and Hartlepool, stood down as an MP but he still provokes strong feelings on Teesside – both good and bad.

Some who responded to our callout blamed him for their loss of faith in politicians, accusing him of using the town as a stepping stone for a big job in Brussels. Others say he brought a bit of sparkle and self-belief to a post-industrial town that had been chronically depressed since the 1960s. Look around Hartlepool and many of its flagship developments have his fingerprints on them: from the continental-style marina that opened in the early 90s, to the new Hartlepool College of Further Education building, home to one of the country’s leading apprenticeship providers.

There is little doubt the Oxford-educated Blairite was an odd fit for Hartlepool – and not only for the now-denied story that he once confused mushy peas for guacamole in one of the town’s chip shops. Far from Mandelson’s fervent pro-Europeanism, Hartlepool is a socially conservative town that can feel disconnected from the rest of the north-east, let alone Britain or Europe.

Facebook Twitter Pinterest Students at the Hartlepool College of Further Education campus. Photograph: Gary Calton/The Observer

But Mandelson won Labour’s biggest ever majority in the town when first elected in 1992, and his popularity increased over the decade. In 2001, election officials rushed to find a table to hold all his votes when he romped home with a 59.1% majority in his famous “fighter not a quitter” victory.

I ask Mandelson how Hartlepool went from electing one of Europe’s biggest cheerleaders to voting so resoundingly for Brexit. “You had a mixture of appalling recession and austerity, poor politics and local leadership, a lot of public anger and a very, very handy protest vote in Ukip,” he says.

It was, in other words, two fingers to the establishment – and that includes the Labour party, which Mandelson believes has faltered badly in Hartlepool since his departure. A series of controversies has beset the town’s Labour-run council, fuelling anger among many voters. The council’s leader, Christopher Akers-Belcher, blames the 11-year mayoralty of Stuart Drummond – the former football mascot who ran for office as H’Angus the Monkey – for causing the town to stagnate. Drummond declined to be interviewed.

Labour’s share of the vote at general elections has plummeted – from 60.7% in 1997 to 35.6% two years ago. Bookmakers have the Tories as odds-on favourites to win Hartlepool for the first time in 53 years.

Brexit gave disgruntled voters an opportunity to lash out, Mandelson says. But he insists the town has not always been Eurosceptic. “In the 90s and 2000s before I left, I remember it being regularly said to me that we get more money and a better deal from Brussels than we do from London,” he says.

“People felt the country was completely unbalanced, it was a London-dominated, southern-slanted economy. There was a real sense of being denied economic justice. The counter to that was when Labour came to office and you had me in the government. Tony Blair in the neighbouring constituency [Sedgefield] and lots of other ministers from the north – suddenly people felt they were being recognised at last.”

Facebook Twitter Pinterest Peter Mandelson, centre, in 1997. Photograph: Martin Argles/The Guardian

Graham Robb, a Conservative candidate in the 1992 election, believes Hartlepool has always been Eurosceptic but that it was willing to give Mandelson the benefit of the doubt because they spotted “a man of exceptional talent”. More significantly, though, he believes the town’s 69.6% Brexit vote was a sign that the town’s latent social conservatism had come to the fore. And that, he says, is why the Tories have a “very, very good chance” of winning the seat on 8 June.

“Traditional attitudes towards this country are coming back to the surface,” he says. “I don’t think it’s sudden, I think it’s more gradual and will be exacerbated by the fact it’s a vacant seat for the first time since 1992.”

Robb runs a public relations firm, Recognition PR, and is the north-east chairman of the Institute of Directors. He says it is an “overstated myth that the Labour vote is tribal in the north-east”. He says “it’s less a left and right thing, more an attitudinal thing” that will determine how Hartlepudlians vote.

Facebook Twitter Pinterest Graham Robb, who stood against Peter Mandelson in 1992. Photograph: Gary Calton/The Observer

“If it’s about the issues I think it probably goes back to core instinct. It’s a socially conservative place and I think the Tories have a very, very good chance of winning it,” he says.

Back in the Cosmopolitan, Fleming scoffs at the idea of a Tory MP representing his home town. “There’ll be a few movements in a few graves if people voted Tory,” he says as the rain pours outside. “I think it’s going to be a case that Labour will get back in. The Conservatives will split the [Ukip] vote and they haven’t got a chance in hell of getting in.”

A former Labour voter and ex-serviceman, Fleming says he ditched the party over the Iraq war before his election as an independent and then a Ukip councillor. He liked Mandelson at first – “he seemed to get things done up to a point” – but says that he is now “tarred with the same brush as Tony Blair”.

“They’re both spin doctors,” he says. “I think up here we call them lying bastards.”

Sipping a beer, Syd Lewis, 69, offers a more complimentary verdict on the former MP: “I thought Mandelson was all right, canny lad.”

Facebook Twitter Pinterest Syd Lewis and Cosmopolitan pub landlord Tim Fleming. Photograph: Gary Calton/The Observer

The retired caretaker says he had voted Labour all his life until 2015, when he voted Ukip “for a change”. He dislikes Jeremy Corbyn. “I was all for him at first but he soon came across as very dull and not a very leader-like person,” he says. He fears Labour would reverse the Brexit he voted for, so will vote Ukip again on 8 June.

Asked what would make him return to the Labour party, Lewis says: “I’d like Tony Blair to come back.”

Despite the former Labour leader’s call for voters to “rise up” against Brexit, a Blair comeback would return a pizzazz to politics, he says, and could thwart the Tories in Hartlepool.

The thought has him reaching for his glass. “That would be one hell of a shock, that,” he says. “One hell of a shock.”