To the perennial complaint that Britain “doesn’t make anything any more” there are few better ripostes than the Brompton Bicycle company. As workers assemble the trademark fold-up bikes at the firm’s factory in Brentford, west London, a screen shows them comfortably exceeding their hourly target rate. It is here that Chuka Umunna is spending the afternoon as part of his Future Jobs tour of the country.

Brompton, the shadow business secretary tells me, illustrates the kind of economy he wants to build: high-skill, high-wage (the average salary is £35,000) and high-export (80 per cent of its bikes are sold overseas). Rather than merely narrating the UK’s failures, Umunna wants Labour to celebrate its successes. He wants his party to appear more optimistic. He wants it, as he says repeatedly, to “own the future”.

“They won’t let me get on the bike!” Umunna complains about his accompanying aides. The risk of a deluge of “On yer bike” headlines is deemed too great for him to hop aboard. “Welcome to my world,” he remarks to one employee.

Forget the bike, though: Chuka Harrison Umunna has travelled in the political fast lane. After his 2010 election as the MP for Streatham, the area in south London where he grew up, the 36-year-old became shadow business secretary just 17 months later. Telegenic, articulate and immaculately dressed (he polls extremely well with focus groups), the former lawyer is one of Labour’s election galácticos. Should his party win, he will be a senior member of the new cabinet. Should it lose, he will almost certainly run for the Labour leadership, and so could eventually become Britain’s first black prime minister.

Two weeks after our visit to Brompton, we meet in Boyce da Roca, a boutique café opposite his constituency office on Streatham High Road. Umunna is in high spirits after the 2-1 defeat of Manchester City by his local team, Crystal Palace, and a morning listening to James Brown. He orders a latte, tells me excitedly that he has “lots to say” and proceeds to offer a tour d’horizon of the challenges facing social democrats.

“One of the things that I’ve been struck by in relation to the campaign – not our campaign, I just mean the general election discussion – is that in some senses it’s been very domestic indeed, when so much of what is impacting on people domestically is driven by global and international forces. If you look at the last three or four months, what has been the one thing that has had the single biggest tangible impact on people’s lives? It’s probably been the fall in the oil price to around $59 a barrel. And so part of our challenge as progressives is how, in the context of globalisation and all these global forces, do we actually build a fairer and more equal and sustainable society?”

Rather than an assault on the right, Umunna’s opening criticism is directed at his own side. “I think part of the problem of the left is that there are a lot of people, and I say the Greens in particular, who simply seek to set their face against the world as it is. Actually, the real challenge for responsible parties that are looking to govern is: ‘How do you embrace these forces and make them work for the most people possible?’”

Unlike some of his Labour colleagues, who speak reluctantly of the need for deficit reduction, Umunna makes a passionate case for fiscal responsibility, deploying arguments more usually associated with the Conservatives. “Frankly, I don’t think that there is anything progressive in spending more on your debt interest repayments every year than you do on housing, than you do on transport . . . That is where there is an argument from a progressive position to be made for balancing the books.”

But there is, he continues, a crucial difference between Labour and the Conservatives. “The Tories want to balance the books, and go beyond that, because they want to hack off chunks of what the public sector does to support people and communities – and those are two very distinct positions. But to deny that you have to balance the books is thoroughly unprogressive, in my view, and we need to make that argument and we need to make it more confidently. Because if we get elected . . . we’re going to have to make some really tough decisions.”

At a time when British politics can feel suffocatingly parochial, Umunna’s perspective is bracingly internationalist. “For progressives, if we’re going back to how domestic the argument is, we’re only going to be able to democratise the market if we do that at a supranational level.” He believes Labour has much to learn from centre-left reformers such as the Italian prime minister, Matteo Renzi; France’s prime minister, Manuel Valls, and its minister for the economy, Emmanuel Macron; as well as the Swedish leader, Stefan Löfven. “We’re all in contact with each other. All of us are talking to each other about how we do progressive values in a fiscally cold climate when we’re all facing international competition and technology changing the way we work.” Umunna, I sense, aspires to emulate the high-water mark of the Third Way, when Tony Blair, Gerhard Schröder and Lionel Jospin set the pace in Europe.

We are meeting in the week that Labour pledged to abolish the non-domicile rule, which allows some wealthy UK residents to avoid tax on their overseas earnings. The new policy is hugely popular with the public (one poll found support of 77 per cent) and Umunna received complimentary texts from some “well-known” business leaders. But does he worry that the cumulative effect of reintroducing the 50p income-tax rate, imposing a mansion tax and abolishing non-dom status will be to deter investment and entrepreneurs? “I’m very clear: I did not go into politics to tax people,” Umunna replies. “We should be very clear about that as a party. Ed Balls and I say it all the time to business audiences because we believe it.”

He adds: “That is why we’re committed to maintaining the lowest rate of corporation tax in the G7 and to ensuring that the tax burden for small businesses is lower than under the current government. But . . . it is reasonable to ask those who earn millions of pounds to make a little bit of a bigger contribution to the society that has helped provide the fruits of their success.”

Does he believe the 50p tax rate should be permanent? “I wouldn’t want to do it permanently because, as I said, I would like to see the tax burden as low as possible. I don’t believe that you tax for the sake of taxing: you tax to fund public services and, currently, to reduce our deficit and our debt.” His stance contrasts with the one taken by Ed Miliband during his 2010 leadership campaign: “I would keep the 50p rate permanently. It’s not just about reducing the deficit, it’s about fairness in our society . . .”

Perhaps more than any other member of the shadow cabinet, Umunna speaks with conviction about the need to reach out to Conservative voters. “We have to have, and we do have, a big-tent approach. I don’t subscribe to this point of view that says, ‘The wrong people voted for the Labour Party.’” He is referring to a Guardian article by Neal Lawson, chair of Compass, the centre-left group with which Umunna was once closely associated. “My father [Bennett, who immigrated to Britain from West Africa] did very well for himself back in the 1980s. What are we going to say to him: that he was too successful to be part of the Labour club?” Of Bennett, who died in a car crash in 1992, he adds: “My dad worshipped Harold Wilson. How dare anybody say that to him?”

Umunna’s past links with Compass and his more recent ties to the Blairite group Pro­gress have led some to accuse him of ideological inconsistency. But this self-described “modern European social democrat” proposes a synthesis. “How we can succeed is by marrying the best of ‘new’ with the best of ‘blue’,” he tells me, referring to the two prominent Labour factions. Umunna wants to fuse the communitarianism championed by Compass with Progress’s “promotion of aspiration and innovative ways of delivering public services”.

The shadow business secretary’s good looks and tailored suits lead commentators sometimes to dismiss him as more style than substance. But he is one of the Labour frontbenchers most engaged in the arena of ideas. Last summer he edited a book, Owning the Future: How Britain Can Make It In a Fast-Changing World, and he speaks frequently to thinkers such as Brazil’s Roberto Unger (with whom he recently co-wrote a New Statesman piece about raising productivity).

Should Labour fail to enter government, he may soon be fleshing out his vision as party leader. I ask him whether he would like to take on the role. “I always listen to Tessa Jowell, who’s like my political mum, who says you’ve got to keep your feet firmly on the ground. And for every person who writes up something like that, there’ll be another slagging you off. So I think you’ve got to keep a sense of perspective and you’ve got to remember in politics that it isn’t about you, it’s actually about the ideas, the arguments and the party."

Does Umunna, who is of mixed Nigerian, English and Irish parentage, think that Britain is ready for a black prime minister? “I always thought that we’d come before the United States because we don’t have such a troubled history as they have with race. I think we can’t be complacent about who we are as a country – an open-minded and multicultural nation that embraces new people and new ideas – and that’s why I’ve been appalled by so much of the rhetoric and commentary that’s emanated from Ukip.”

For now, Umunna, one of Miliband’s early supporters, is keen to laud his leader. “I always thought the more people saw of Ed, the more they would like him. One of the things that the Tories have massively underestimated in this campaign is the extent to which the characteristics that people attribute to Ed – honesty, decency, integrity – are an asset to our party. They totally and utterly underestimated that.”

When I ask him what he would most like to achieve as business secretary, his response reminds me of our visit to Brompton. “I think ensuring people have better-paid, more fulfilling and secure work is the big thing for me . . . The best way that we can actually close the gap between the rich and poor and lift more people out of poverty is to grow the sectors that deliver better-paid jobs in the first instance.”

It is jobs that are likely to define Umunna’s future, too, and in time perhaps he will have a chance to do the biggest job of all.