On the evening of 22 May, Andy Burnham was at home watching Newsnight having just returned from a game of five-a-side football. When he was called by his friend Steve Rotheram, the mayor of Liverpool City Region, Burnham initially ignored his phone. “But then he called again and I realised it must be something important.”

The Manchester Arena, where Rotheram’s daughters were that evening, had been targeted by a suicide bomber. “Like everybody, I felt sick to the pit of my stomach,” Burnham recalled when we spoke recently. “You feel it every time you hear of a terrorist attack, but to have one so close to home...”

At the time of the attack, which killed 22 people, Burnham had only been in office for two weeks. The incident, the worst the UK had endured since the 7 July 2005 bombings, was a severe test of the Greater Manchester mayor’s leadership. But he was prepared.

“On day one in the job I’d sat down with the chief constable and asked him outright: ‘Are we ready? Are we prepared for another terrorist attack?’” Burnham told me. “The reason I did that, I suppose, comes out of my background at shadow home... If you look back, a big theme of mine during that period was challenging Theresa May [then home secretary] about whether regional cities were as prepared as London for a terrorist attack.”

He added: “I got assurances on day one and they were real assurances because Greater Manchester (GM) had been planning. The NHS had, in fact, planned for an attack on the arena a few weeks before. While I did feel sick to my stomach and anxious about what was happening, the strength of GM was immediately apparent to me.”

Burnham described the city as “recovering” (the arena reopened with a concert on 9 September) and emphasised that it was “a long process”. “I’m meeting the families on a fairly regular basis. We’re beginning discussions about appropriate ways to create a memorial to the victims.”

The mayor has established a new commission on tackling violent extremism, led by Labour councillor Rishi Shori, the leader of Bury Council, and believes that Prevent, the government’s counter-terrorism programme, is critically flawed. “It doesn’t have the confidence of the people it needs to have at the moment. If the flow of information isn’t coming up from families and communities and faith organisations then it won’t work”.

The last time I interviewed Burnham, in August 2015, he was struggling to put a brave face on his inevitable defeat to Jeremy Corbyn in the Labour leadership election. In the ensuing period, Burnham was pilloried by former allies for his subsequent loyalty to Corbyn (he did not join the mass shadow cabinet resignation in June 2016). But as mayor, the 47-year-old former health secretary is a politician reborn.

On the morning I was due to meet Burnham, a fire on the London-Manchester line had halted all trains. We arranged to speak by phone. “Devolution can really change politics, it could begin to provide an answer to the alienation we’ve seen growing over many years and that culminated in the EU referendum result,” the mayor told me as he reflected on his opening months in office.

Burnham, who was MP for Leigh from 2001-17, and previously a special adviser to culture secretary Chris Smith, spoke disdainfully of his former workplace. “The Westminster system is set up institutionally to promote point-scoring, isn't it? It’s built into the foundations of the place. It is quite liberating to leave that totally behind and just focus on place and people and making a difference.”

One of Burnham’s policy priorities has been tackling homelessness in Greater Manchester (which has quadrupled since 2010 to 4,428 people). He donates 15 per cent of his £110,000 salary to a homelessness fund and will do so as long as he is in office.

Though Burnham has vowed to end rough sleeping in the region by 2020, he conceded that “the problem seems to be getting worse”. “But my commitment doesn’t diminish. I’m not going into that mode of saying: ‘It’s all somebody else’s fault’”. On the morning we spoke, Burnham wrote to all public bodies demanding “immediate steps” to address the crisis.

The mayor spoke of his desire for further devolution, such as the transfer of the welfare budget. “Steve [Rotheram] and I were in New York earlier in the summer, with mayors from the US and Europe. And in the States, where there’s a long tradition of mayors, there’s a clearer analysis that Washington has always been dysfunctional, to a degree, and that it’s become more so under Trump and, therefore, change is going to be driven by city regions.”

In the case of the UK, Burnham believes that “our antiquated, London-centric system” is similarly cumbersome. “The Brexit debate has brought that out and I feel strongly that it’ll be city regions that drive the quickest and most progressive change in the future ... Manchester has an incredible history of radical forward-thinking, of social disruption, industrial innovation. We’re being absolutely true to our roots in being at the forefront of this movement towards devolution.” I am reminded of the words of Factory Records founder Tony Wilson: “This is Manchester, we do things differently here.”

Burnham joined Labour as a 14-year-old having been “radicalised” by the 1984-85 miners’ strike. On 4 May this year, he was elected mayor by a landslide, winning 63.4 per cent of the vote and achieving support in Conservative areas such as Bolton West and Altrincham & Sale West.

I asked Burnham, who finished second to Corbyn in the 2015 leadership election (winning 19 per cent to his opponent's 59.5 per cent), whether he ever contemplated how Labour would have performed under him. “No, that’s in the past, as far as I’m concerned,” he replied. “I feel I’m in the right job at the right time. I genuinely don’t spend time on that.”

Burnham did not join Corbyn at the victory rally that followed his mayoral election, explaining that he was too busy (he was later pictured drinking champagne with his team at The Refuge restaurant). At this year’s Labour conference, Burnham, like his London counterpart Sadiq Khan, has not been accorded a speaking slot.

“Well, it’s a matter for the party and the powers that be ... I’ve always respected that,” Burnham said when I raised the subject. But he added: “What I would say, and it’s no divine right of mine to be there, is that if elected mayors aren’t to be given any role, I think the party needs to think long and hard about how it demonstrates its commitment to devolution.

“And its commitment, more directly, to the rest of the country, the regions. I’ve criticised the party in the past for being too London-centric and I will always challenge it. There is a tendency to be London-centric in the Labour Party and that tendency needs to be constantly challenged.”

Four of Labour’s keynote speakers represent north London seats that border each other: Corbyn (Islington North), Diane Abbott (Hackney North and Stoke Newington), Emily Thornberry (Islington South) and Keir Starmer (Holborn and St Pancras). A fifth, shadow chancellor John McDonnell, is another London MP (representing Hayes and Harlington).

Burnham did not disguise his displeasure with the arrangement. “Obviously the shadow cabinet needs a prominent role, but Angela Rayner [shadow education secretary], what a fantastic voice. Andrew Gwynne [shadow communities secretary], what a fantastic ambassador for the party, rooted in his home region. Debbie Abrahams [shadow work and pensions secretary] doing tremendous work.

“I’m all in favour of more grassroots involvement, and fewer set-piece speeches, I understand why the party may want that. But I think it is important that the voices of all regions ring out at conference. I don’t think it’s mine or anyone’s right to expect a platform but I do think the party needs to demonstrate both its commitment to devolution and to the regions more broadly. If it’s not to do that through inviting someone like me, then it needs to do it a different way.”

Burnham also warned the Conservative government not to marginalise the UK’s regions during the Brexit negotiations. “After a lot of challenges, we’ve finally been offered a meeting with David Davis [the Brexit secretary], this is Steve Rotheram and I, and the Teesside mayor [Ben Houchen], on the Friday after the Tory conference. Well, OK, I’m grateful for the meeting but that isn’t a good enough response, I have to say.”

He continued: “There could be trade-offs here, couldn’t there? The City of London is something that the government will want to protect; are other industries going to pay the price for that?” With a view to strengthening the regions’ voice, Burnham is discussing the formation of a “council of the north” which would assemble twice a year.

Burnham backed Labour’s support for EU single market and customs union membership during a “transitional period” but emphasised: “We also have to demonstrate, and continually stress, that we respect the result and will respond to the concerns that clearly were articulated by many Labour voters up and down the country in the referendum.”

I end by asking Burnham whether he would ever consider returning to Westminster to seek a national leadership role.

“I don’t see this as a stepping stone,” he insisted. “People might think, ‘he’s just biding his time up in Manchester’. I don’t think of it like that at all. For me, this is a new chapter in my political life, which I’m very fortunate to have. I’m devoting myself to it wholeheartedly, I don’t do anything by halves. I’m not really a tactical politician in that way. If I do something I try and embrace it wholeheartedly. I’m doing it in that spirit and I hope to be here for the long-term.”