In London, at some point in the 1840s, an oyster seller who had “seen better days” described her trade to journalist Henry Mayhew. Hawking from a basket on a busy street, she took home just a shilling a night (£2-3 today). Her regulars were sheepish gentlemen, prostitutes, and workers hunting a Saturday supper. In nineteenth-century London, oysters were hardly a luxury. Mayhew estimated 124m were sold every year, at four a penny.

In the same city, in mid-2016, I picked up dinner in a half-abandoned warehouse. For a few pounds entry, plus a fiver or so a dish, I wolfed down Hawaiian sushi, a Jerk-seasoned corn cob, and chewy, bright-green meringues. The vendors and bar staff were even hipper than the hip, millennial crowd, which was padded out by families and tourists.

Street food has always been an urban phenomenon. A set of historical essays, published this summer, has chapters on ancient Rome, Naples in the 1700s, and modern-day Bangkok. Until recently, rich and poor cityfolk bought most of their food, raw and cooked, from stalls or wanderers on the streets.

It’s hardly news this traditional chow has gone gourmet. Open-air markets, like Smorgasburg in Brooklyn or Kerb across London, jostle with restaurants to offer the most exciting and innovative urban grub.

But another trend could change the phenomenon, and the city space, more drastically: the fixed-site, often indoors, always open market. Street food is coming off the streets.

This autumn, Time Out unveiled plans to open a market in London during the second half of 2017. The Shoreditch site will host 17 food outlets, a cooking academy, several bars, a shop and a gallery.

“We want to offer local restaurateurs, mixologists [that is, cocktail-makers], artists the opportunity to showcase their talent in a different part of town and in a great location that reflects our brand character,” Time Out CEO Julio Bruno told me by email.

London is not the only target. In 2014, the media group opened its first market in Lisbon, taking over a 75,000 sq ft, nineteenth-century hall on the waterfront. A second Iberian market, in Porto, will start trading next year. Similar schemes in Miami and New York are “progressing well”, the company says, but have no launch dates attached.

Time Out stresses these markets are not just about street food; journalists say otherwise, drawing them into round-ups of on-the-hoof eating. I visited the Lisbon market in September and saw a dual identity. There was street-style informality: on that Saturday night, the masses fought for free chairs, drunk beer from plastic glasses, and chomped overflowing burgers and bold-flavoured ice cream from semi-permanent stalls. But there were luxury flashes: the hall was decked with polished wood and steel, and the vendors included some of the city’s best-known chefs, who crafted elegant small plates. As we walked in, passing a glass tank, we were watched by a pair of lobsters.

The market does not mirror the serendipity of street life. Time Out’s writers curate everything, with each vendor brandishing a four- or five-star review. “The best fine-dining, the best fast-casual – [the journalists] handpick all of that, whether it’s already loved by locals or up and coming,” Bruno says.

These markets are a new way to use old spaces. Markets themselves aren’t novel – they were one reason cities first sprung up, and now famous hubs like Barcelona’s La Boqueria, Berlin’s Markthalle Neun and LA’s Grand Central Market have substantial street food components – but this trend is different. These are fresh developments pulling plugged-in food lovers to quieter parts of the metropolis.

Time Out’s Lisbon market played a role in its area’s revival. The Cais do Sodré area, long distinguished by drunk sailors, brothels and sweaty clubs, has become a fashionable nightlife spot over the last decade. Having an attraction feeding 1.3m people a year in your locale can’t hurt. Unsurprisingly, it’s something Bruno is proud of. “The market played a decisive role in bringing employment and attracting visitors to this once slightly neglected part of town,” he adds.

One of Time Out’s competitors has community values up front. London Union’s internal mission statement is, “Transforming lives and communities with the awesome power of street food”. Last year, the company bought Street Feast, which runs markets in underused buildings and spaces in Canada Water, Lewisham and Shoreditch. The one I visited this summer, in Dalston Yard, has recently closed.

Its founders, backed by food world glitterati from Jamie Oliver to Yottam Ottolenghi, want to open to 20 local markets by 2020, including a vast street food mecca in the heart of the city. Their dream spot is the derelict Smithfield General Market.

Smithfield General Market. Image: JamesK1987/Wikimedia Commons.

On the phone, Jonathan Downey, one of the founders, rejects the accusation the smart and fashionable just come to make fun in poorer parts of town. As those areas become cooler, they also become more expensive, rents rise and locals might suffer.

“I am not a gentrifier; I am a hyper-local,” says Downey. He describes the varied parts of London in which he’s lived or opened bars and restaurants. “I’m not a landlord. They may then follow and reference what I’ve done, but I have actually done something that is reasonable and good value. We are about community and amenity.”

Who are these markets for? London Union says 70% per cent of its 1m annual customers are under 35; but the story of invading hipsters is not entirely fair. In Lewisham and Dalston, where 40 per cent of visitors lived within a mile, the markets became part of the neighbourhood, while in Shoreditch the crowd has more suits from the nearby City.

Street Feast’s traders, who pay a percentage of their takings as a pitch fee, hardly resemble the down-and-out hawkers of history. Downey calls most of them “passionate, second- or third-career people”. “They want to do something that they love and share it,” he says.

These warm, structured, permanent markets are a platform for young businesses. Their impact on an area probably needs careful watching, as it will vary from place to place. Rich cities with few vendors may have to worry less, though others, like New York with its several thousand legal and illegal traders, may see a threat.

But what of those defining labels – “food” and “street”? To Downey, street food means specialising in one dish, like chicken wings or tacos. It is anything eaten standing up, but not necessarily outdoors. And it requires a human connection between seller and eater. “It’s a bit like being a band on stage,” he says. “You feel your feedback.”

With the last part at least, Mayhew’s oyster maid would agree.

Charlie Taverner tweets as @charlietaverner.

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