On the night of the election, Jared O’Mara, the Labour candidate for Sheffield Hallam, arrived at the count at 1.30am. Contrary to popular belief, he was not wearing a suit bought just moments before from Tesco, but a pair of his own jeans and a blazer on loan from his father. Hallam, after all, was a safe Conservative seat until 1997, when the Liberal Democrats took it; the idea that it might now fall to Labour was a little outlandish, even to him. No need to go overboard. Half an hour later, though, and he had reason to be grateful for the raid on his dad’s wardrobe. “That was when they told me to start writing a [victory] speech, and half an hour after that, I was making it,” he says. It wasn’t a particularly fluent address. The number of hesitations involved was, he jokes, at least as high as the number of leaflets his new constituents received from the Liberal Democrats during the campaign. But never mind. He had something better than words. In his hand, metaphorically speaking, was the scalp of Nick Clegg, the former deputy prime minister.

After it was all over, O’Mara retreated to West Street Live, the bar and music venue that he and some friends run near Sheffield University (in the press, he has been described, correctly, as a disability campaigner, but his day job is at this hugely successful business). “There may have been some refreshments, and I may have gone home at 6am,” he says. Later that morning, he did a press event at Forge Dam, a local park, after which he headed for the city hall to speak at a rally against Theresa May and her hoped-for arrangement with the DUP. There, a party worker gave him a beautiful bouquet of flowers, which was handy because “it was my nannan’s 90th birthday party the next day, so I took them to her”. On Saturday, he had a much-needed day off. On Sunday, he had some meetings, and on Monday, a get-together with the volunteers who’d worked on his campaign. Finally, on Tuesday, he arrived at Westminster, which is where we meet, our conversation constantly interrupted by MPs and others eager to congratulate him. As yet, he has no office, no staff, and no London base (he’s staying at a hotel). But all these things are in the process of being fixed. A more immediate worry is whether he’ll find the time to catch Wonder Woman at the cinema. “Hopefully, I’ll see it this weekend,” he says. “But there’s so much to do.”

In the days after the election, the press made much of the fact that O’Mara has cerebral palsy, and it was right to do so. But while his disability has undoubtedly had a profound effect on both his life and his politics, in truth it isn’t this that makes him so unusual an MP. Rather, it is that he comes across as a real person, as opposed to a robot pretending to be one. A 35-year-old Marvel comics geek who loves Douglas Coupland, Buffy the Vampire Slayer (“I worship at the church of Joss Whedon”) and Sheffield Wednesday, he’s the kind of bloke who likes nothing better than to spend an evening singing drunken karaoke at Dempsey’s, a Sheffield LGBTQ bar. When I ask if he is single, for instance, he doesn’t just tell me that, yes, he is. “I’m open to offers,” he says. And then, after a music hall pause: “No gold‑diggers, though!”

O’Mara giving his victory speech after defeating Nick Clegg in Sheffield Hallam. Photograph: Darren O'Brien/Guzelian

He was surprised to win Hallam: when he was selected, he hoped only to maintain the margin achieved by Oliver Coppard, who stood for Labour in 2015 and came second. And even now, a week on, there are moments when it feels like he’s in a movie. “I keep comparing myself to Forrest Gump,” he says. “I’m this slightly eccentric, little bit weird disabled guy who keeps stumbling into large achievements.” However, this isn’t to say that when it comes to politics he isn’t deadly serious. “If you put it in crude terms, I’ve gone from working in a pub to being an MP. But it’s about time we had some more normal people round here. I’m the right side of 40, and I’d like parliament to stop patronising the young. I don’t see any reason why we can’t have, in the future, 18- or 19-year-old MPs. We’ve seen Mhairi Black [the SNP MP who was 20 when she was first elected]. She has done a fantastic job. She hasn’t let anyone patronise her, and I’m going to have to do the same, because I’ve got a baby face.” He gives me a look. Do I want to know the secret of his youthful visage? “It’s down to mineral water, steamed vegetables and 20 fags a day.”

Why did he win, though? Hallam is one of the richest constituencies in the country. It has low levels of child poverty, and high numbers of voters classified as professionals. Parts of it are semi-rural. If it is full of students, who turned out for him in large numbers, it is also a realm of ancient trees and big detached houses, for which reason Labour’s victory there is on a par with its success in Kensington. O’Mara, though, doesn’t quite see it that way. “I reject the idea that it’s rich. There is so much diversity. In Dore [a plush suburb where footballers like to live] there are some very humble, working-class people who’ve retired there. When I knocked on doors in Stannington [one of the less well-off areas], people were switching back from Ukip because they felt our manifesto would look after them.”

I think this might be a weird sort of wishful thinking: what he doesn’t say is that he also benefited from the increase in the Tory vote, an upswing that surely had its own effect on Clegg’s majority. Still, he is determined to represent the rich as well as the poor. “In my own family, I’ve got that duality. Latterly, my dad ended up with a decent wage. They invested well, and were sensible, and retired early with no mortgage and a nice detached house. I appreciate both sides.” (Momentum has, incidentally, tried to claim Hallam for one of its victories. But O’Mara isn’t having this. “No, no. I reject that entirely. I was grateful for their help, but it was a victory for every shade of red in the party. There are some really good eggs in there, but there are also a few people that… well, I maybe want to put a bit of distance between them and myself.”)

O’Mara: ‘I can’t wear a shirt and tie because I can’t do the buttons. I’m going to be wearing plain T-shirts in Westminster, which is against the dress code.’ Photograph: Jon Super/The Guardian

And what about Brexit? The line is that Clegg was punished for being too pro-Remain. O’Mara is a Remainer, too, but in a party whose leaders have said that Labour policy is for Britain to leave the single market, in a city that voted Leave, in a constituency that voted to Remain. Maybe he was able to play it both ways. So what does he make of Jeremy Corbyn and John McDonnell’s recent statements on this subject? Finally, the politician clicks in: “I think we want the best trade deal for the economy and that’s what Remain voters want, and we want to maintain the rights of EU nationals. Of course I was sad about the vote [for Brexit], but at West Street Live we’ve got a Romanian, an Italian and a Pole [at this point, he shouts out their names into my tape recorder, in the manner of a DJ] and I’ve said to them I want to fight for them to stay in Sheffield.”

Meanwhile, his constituents continue to worry about their glorious, irreplaceable trees – the company the Labour council employs to take care of its pavements keeps cutting them down, in the face of angry protests – and their threatened libraries. (I know this because four members of my family and my oldest friend are among them.) Again, the politician speaks. “I can’t talk about the trees too much,” he says, a bit bizarrely. “Things are more complex than what is in the public domain. I have a lot of sympathy for the tree campaigners, but I also have sympathy for the pressure our Labour council is under. Why are the libraries under such strain? Because of the cuts to council budgets that have come from the Tories. We have got to fight to get more money from central government.”

There has been nothing the current leadership has done that I don’t agree with

O’Mara, who joined the Labour party at 17, didn’t grow up in Hallam, and doesn’t live there now, but he did do his A-levels at a school in the constituency. His dad is a retired train driver, his mum did various jobs including working in a chip shop, and there is trade unionism on both sides of the family [his maternal grandfather, having helped to liberate Naples during the war, was active in the union at the steel mill where he worked afterwards]. “I wouldn’t be the person I am without my parents,” he says. “I well up thinking about them.” His cerebral palsy was diagnosed when he was six months old, the doctors telling his parents that their son would probably be in a wheelchair all his life. “But they always had my back, and it’s thanks to their resilience, and the help I got from the Ryegate Children’s Centre [a Sheffield NHS service for disabled children], where I had so much physical therapy and speech therapy that I got to a point where, unless your eye is trained, you’re not going to know about my disability.”

How does it affect him now? “The entire right side of my body is semi-paralysed or significantly weaker than the left. My main symptom is fatigue. I can’t stand for long, or walk about too much. Mobility is an issue. Some stairs are too difficult if they’re narrow and steep – I need banisters on both sides – and I can’t wear a shirt and tie because I can’t do the buttons. I’m going to be wearing plain T-shirts here [Westminster], which is against the dress code.” Was he bullied at school? “I had some really good, loyal friends, but, yes, it was not uncommon for me to get beaten up.”

After studying journalism at Staffordshire University – he got a first-class degree – he worked as a campaigns officer for the British Council of Disabled People. But then the chance came to turn his passion – for DJing and organising live music – into a business. “So my hobby became my job, and my job became my hobby. We’ve made West Street Live into one of the most popular nightlife destinations in Sheffield. But I’ve always volunteered and fund-raised. I am a governor and trustee of Paces, which is a school and community resource for disabled people.” Seven years of austerity have, he says, brought devastation to the disabled. “This narrative of scroungers. Not only do you now have to submit medical evidence, you have to go through a humiliating examination by someone who’s not even a medical professional.” In parliament, he hopes to have the chance to fight for the restoration of legal aid for equality cases. “We’ve got a lot of rights enshrined in law, but you can’t uphold that law if you don’t have access to the system.”

Will he be a loyal Labour MP?

“There has been nothing the current leadership has done that I don’t agree with,” he says. Nevertheless, he is clear that his first duty is to his constituents, and the city he loves. As he points out, unlike Nick Clegg, he is a “proper dee-dar” (this is what people from Barnsley call people from Sheffield, on account of the fact that they say “dee” and “dar” instead of “thee” and “thar”). “Sheffield is my home. I have a deep connection with it. Without my constituents, I am nothing.” He believes there will be an election sooner rather than later, and when it comes, he will be more than ready. “We will win, and we will form a government, and I will increase my majority.”