‘I don’t think anybody can ever say that a city is complete,” says Sir Howard Bernstein. “Cities constantly reinvent themselves, and there are different phases in a city’s transformation. So the job’s never done. I could be here for another 50 years.”

He laughs at the absurdity of the thought, but it’s not hard to see what he means. A stone’s throw from where we are talking, there are sights that will be familiar to any visitor to modern Manchester: a skyline dotted with cranes, innumerable new buildings, and endless gangs of construction workers. As ever, the city feels impatient, and restless.

Bernstein turned 64 this month. From 1998 until March this year, he was the chief executive of Manchester city council – as he saw it, therefore “the chief executive of Manchester, the city”. In 2011, he also became the de facto boss of the Greater Manchester combined authority, which blazed a trail for English devolution, and will see the election of its first mayor this May. In between, alongside long-standing Labour council leader Sir Richard Leese, Bernstein enacted one of the great modern British stories – of Manchester’s reinvention, from being locked into a post-industrial decline, to the young, thriving metropolis it is today.

By any measure it is quite a tale, involving two bids for the Olympics, a hugely successful Commonwealth Games, and an IRA bomb. The saga opens with early examples of regeneration – “little nuggets”, Bernstein calls them – such as the legendary nightclub-cum-venue the Haçienda, and the early stirrings of entrepreneurialism in the hipster honeypot now known as the Northern Quarter; its latter stages involve China and Abu Dhabi, Manchester’s place at the heart of the “northern powerhouse”, and billions of pounds of investment.

One of the great modern British stories ... the reinvention of Manchester. Photograph: Alamy Stock Photo

The story will go on, but Bernstein’s role is now at an end. “Every two or three years,” he tells me, “I’d always said, ‘What do I want to do over the next two or three years?’” When he last mulled it over he began to wonder whether he could guarantee the same level of commitment he had managed for the last 20 years. “And when someone like me starts getting thoughts like that, you really do need to sit down and think about succession.”

Bernstein is in his new office at Manchester University, where he has just been appointed professor of politics, a role whose fine details have apparently yet to be decided. He will soon start a part-time job with the global consultancy firm Deloitte, “focusing on cities, and what makes them work”. His intention is to still work five days a week, as opposed to the seven he is used to.

With distinct sartorial echoes of Tony Wilson, he wears a navy blue suit with matching trainers and has a soft, deep, lived-in voice. Though he often lapses into officialspeak, using words like “access, “amenities” and “holistic”, he tends to quickly spring back out.

Bernstein has the kind of up-from-the-bottom career story that is now so rare as to seem almost incredible. He was born to Jewish parents in the Cheetham Hill area of the inner city – his father made his money selling raincoats – with paternal grandparents who had come to Manchester from Russia. Having left Ducie High School at 17, he started work in 1971 for what was then the Manchester Corporation, as a junior clerk. The first task he was given was washing teacups – but he was soon studying for an external law degree, and gradually making his way up the council hierarchy, in a professional world stubbornly stuck in the past.

The only women he saw were filing clerks, and even close colleagues addressed each other using “Mr” and “Mrs”. Worse, the people he worked with had a grim view of Manchester. “The whole idea was, ‘Let’s put council housing wherever we can’ – thinking that the only way we could drive the future of the city was by building hundreds and thousands of council houses. There was no understanding that successful cities are really about how you attract people who have got money. And of course, when I used to talk about all that they used to look at me like this …” His face assumes a look of mock-horror. “We didn’t have a strategy for culture, or sport, or science – we didn’t have a strategy for anything, really.”

From the early 1980s, more forward-looking ideas gradually began to cohere. Bernstein, some of his fellow council officers and a new clutch of leftwing councillors started to think about what we now call regeneration, and how to use their power to bring jobs to a city in dire need of them.

Corporation Street after the IRA bomb explosion in 1996. Photograph: ANL/Rex/Shutterstock

In 1991, they demolished the infamous Crescents in the inner-city neighbourhood of Hulme: vast housing blocks, ridden with structural defects, which symbolised the city council’s failings – and worked with an array of companies and housing associations to give the area a new start. At around the same time, the city council launched an audacious bid for the 1996 Olympics (“a leap in the dark”, says Bernstein), which were succeeded by a more serious stab at the 2000 Games, only for the honour to go to Sydney. “We thought we were going to come second or third. And when we found out we were the second city to get knocked out, it was a shock. It desperately hurt.”

That disappointment came in 1993; three years later, a whole chunk of the city centre was destroyed by an IRA bomb. Bernstein heard the explosion while he was at a wedding in Cheetham Hill. Having worked on plans for a comprehensive rebuild partly inspired by Barcelona, he and Leese then went to London to ask for financial help from deputy prime minister Michael Heseltine. “We took him through the plan, explained the timescales, and he said, ‘Well, fine – how much do you need?’ I said, ‘It’s £97–98m.’ He said, ‘Right – I’ll get in touch with you as soon as I can.’ And by the time we got out of the cab at Euston, he said, ‘Right – I’ve got the money.’”

Bernstein became chief executive two years later. Then, in 2002, Manchester hosted the 17th Commonwealth Games, firmly putting Manchester on the international map. But he didn’t have an easy time. “My backside was hanging out of the window on it, from start to finish. The control that I’d been used to wasn’t there: it was, ‘Well, actually, I can’t control the weather, I can’t control the security, and I can’t control the money side as much as I want.’ And we were given a very hard time by the government. A Labour government, I hasten to add.”

Manchester’s Commonwealth Games ... ‘My backside was hanging out out of the window on it, from start to finish’ says Bernstein. Photograph: Laurence Griffiths/Getty Images

They were being difficult? “Oh God, yeah. Labour ministers didn’t want to give us much money. It was, ‘It’s your Games, you bid for it, you fund it.’ It was ultimately Tony Blair who intervened and said, ‘We want this to be a success – why are we giving these guys such a difficult time?’ Because of our pragmatism in working with a Conservative government, particularly during the late 80s and early 90s, it was another example of how Manchester was seen by some people in the Labour government: ‘Well, you sold out to the Tories.’”

That was clear? “Absolutely. John Prescott spent most of his life telling me that on a daily basis: saying that there were things we were denied, in terms of support, which were only rationalised on the basis of, ‘Manchester should be punished for working with the Conservatives’.”

In the wake of the Brexit referendum and Theresa May’s arrival at No 10, it now seems like something from a different age – but it was in June 2014 that chancellor George Osborne made a big speech in Manchester announcing the birth of what he called the northern powerhouse, and a plan in which Bernstein was soon fully involved. Osborne talked about “joining our northern cities together … by providing the modern transport connections they need; by backing their science and universities; by backing their creative clusters; and giving them the local power and control that a powerhouse economy needs.”

Some of these plans have now materialised, not least when it comes to devolution – as of April last year Greater Manchester became the first English region to be given control of its health and social care budget. Bernstein, however, says the Manchester region is hungry for even more powers, not least over economic policy. But with Osborne out of power, the dedicated northern powerhouse minister Jim O’Neill no longer in post, and May’s government preoccupied with Brexit, is he worried about the project’s future?

“The government has gone out of its way to say that the northern powerhouse is part of its economic policy for the future,” he says, before pausing. “The proof of the pudding will be in the eating, when they have to make big decisions about investment.”

This, he says, will all become clear in the coming months. “If these things are endorsed, the northern powerhouse is alive and kicking. And if they’re not … Well, we’ve got to hold the government to account, to deliver on the promises.”

What should people keep an eye on? “The Manchester-Leeds railway. The Liverpool-Manchester railway. Connecting Sheffield to Manchester, and Sheffield to Leeds. The delivery of HS2. These are all transformative investments which are absolutely essential.”

‘Inspirational figure’ ... George Osborne launches the ‘northern powerhouse’ partnership at Manchester town hall. Photograph: Paul Ellis/AFP/Getty Images

Does he miss Osborne? “Yeah! Because George Osborne was an inspirational figure. Devolution would not have been possible without a senior figure in government taking responsibility for it. George Osborne played a fundamental part. He gave real political and economic credibility to the northern powerhouse strategy.”

How did Bernstein feel when he heard that Osborne had perhaps spoiled his northern credentials by taking his job at the London Evening Standard?

“I laughed,” he says. “I never knew about that. But look: at the end of the day, he’s a top guy.”

A lot of Labour people will really like that kind of talk.

“Well, you’ve got to give credit where it’s due, haven’t you? When we had a Labour government, Manchester never had devolution. I’m not even sure we’ve got a Labour party that talks about it very much at the moment.”

Aside from the future of the northern powerhouse, there are other uncertainties hanging over Manchester’s future. Some relate to the city council, and what it does: Osborne may have been one of the prime movers behind Mancunian devolution, but he was also chiefly responsible for the cuts that took 40% out of Manchester’s budgets over the past six years. “I don’t think anybody thought there didn’t have to be reductions in public spending, but local government disproportionately took a hit,” says Bernstein, diplomatically.

And then there is Brexit. Bernstein says that as much as £500m of EU money has been spent in Manchester in the past five years alone, and is at pains to point out that much of the city’s success has been built on both the free movement of people, and collaboration with no end of European organisations, as well as continental cities. “Anything that starts to threaten that network of collaboration and movement will be a significant threat to the future,” he says. “I think we face a real period of uncertainty over the next couple of years.”

His face darkens for a moment, before I ask him about how much the city has changed since his days washing teacups, and whether he has moments when the new Manchester suddenly reveals itself anew. “Part of my problem is, I never really look backwards, so I’ve never really spent time appreciating some of the things that have happened in the city,” he says. Nonetheless, he says he does have occasional moments when he surveys the skyline, or catches sight of some new development, and gets a sudden sense of transformation.

“There have been remarkable things achieved in Manchester over the last 10 or 15 years,” he says. He then suggests that any kind of retirement will have to wait. “But we’ve got to do more.”