Vans are serving up classy dishes from authentic burritos to luxury chocolates. Alice-Azania Jarvis steps aboard

It is midday on Leather Lane and the heavens have opened. Stall holders lurk, limply, eyeing the empty market. The frequently bustling corner of London has been emptied of its usual custom by the sudden downpour. All, that is, apart from a corner patch mid-way down the cobbled street. With the smell of chilli and coriander hanging in the air and a queue of at least a dozen customers, the Daddy Donkey burrito truck is still very much in business.

In the six years since its inception as – in the company's words – "a rickety stand" on Brick Lane, east London, Daddy Donkey has won a loyal following among the city's lunchers. Joel Henderson, the business's owner and founder, showed me photos, taken on his phone, of customers queuing in December's heavy snow. "It was so good to see that," he enthuses. "Just the fact that people are willing to make the effort for our food. It's great."

Henderson and his team – a core staff of five-odd cooks, servers and burrito-rollers, plus several freelance or shorter term members – cope well with the demand. Joining the waiting masses, I'm giving my order in less than a minute: A Daddy D Burrito with carnitas. Huge, crammed with slow-cooked pork shoulder, rice, black beans, salsa, lettuce, sour cream and guacamole, it is a lot of food for £5.50; good food, too. Spicy, saucy and piping hot in its tinfoil parcel, the Daddy D is a pretty faultless meal for a rainy lunchtime.

My fellow diners don't linger. They head back – frequently with multiple orders in hand – to eat at their desks. In warmer weather things might be different, though the portability of Joel's creations is part of their appeal. Indeed it is one reason why the food truck has become an increasingly visible presence on the British high street. With food-on-the-hoof an ever-expanding market it was just a matter of time until the burger van got a gourmet makeover.

"I've always found it incredibly frustrating when I've been running around town and there's nothing good that you can eat in a hurry," agrees Mark Jankel. Formerly head chef at the Notting Hill Brassiere, Jankel established the Street Kitchen food truck alongside Jun Tanaka, executive chef at London's Pearl restaurant, last year. The pair made their debut at the London Restaurant Festival. "Our concept was basically to take the techniques we employ as Michelin-trained chefs and simplify. For us, it was all about good local produce. Everything was British. Our veg would arrive at midnight and then we'd be serving it the next day. People could really taste it."

Jankel and Tanaka spent October dishing out classic bistro-style dishes – hot-smoked salmon, braised beef, artichoke soup – at easily affordable prices. The result was a runaway success with the public and plans are afoot to establish a more-permanent set-up this year. "We've just got a production kitchen and by the end of the year we'd like to have two vans in the city."

Together with Henderson, Jankel and Tanaka represent a small part of the revolution in British street food. Alongside the gourmet farmers' markets that populate the weekends, the food truck offers a whole new way to enjoy eating on the go. And they're not alone in their adventures; a growing community of mobile street vendors is carving out its place on the British culinary landscape.

"It is a slow-burning movement," agrees Petra Barran. "It's a natural progression really – it has been bubbling away for some time." An early adopter of the trend, Barran's own truck, the Choc Star Van, specialises in all things cacao. Making the most of her mobility, she rarely stays in one place for long, moving from one town to the next – frequently staying with fellow chocolate lovers met through her blog or Facebook page. Last year she set up the Eat Street website, connecting the country's food trucks with one another – and with their customers. Here are mobile foodies selling everything from gluten-free tagine to omelettes and, of course, ice-cream. "One of the best things about the whole thing is the variety. The vans aren't just white boxes dishing out grease – they have personalities," Barran says.

Perhaps we should have seen this coming. After all, with every other aspect of British dining – the pub lunch, the street-side café, the market stall – having undergone a steady foodie-fication over the past decade, the lunch van was the next logical step. In the United States, food trucks have been selling high-quality meals for some time. In Philadelphia, options range from fresh fruit salads at breakfast time to Carribean food at lunch to spit-roast pork for dinner. Los Angeles and New York have seen the trend taken further: trucks specialise in everything from Korean barbecue, sushi and dim sum to buttermilk and shaved ice. And then there are the manifold coffee carts that have established themselves outside train and subway stations. Offering decent espresso and a selection of café-quality pastries, they have pioneered the mobile market.

Evolving in tandem with this, the internet has become a crucial tool for the new generation of van vendors. Alongside the Eat Street and Choc Star websites, Barran runs a blog and has some 1,150 followers on Twitter. Jankel and Tanaka, too, have a sizable online following – though it is perhaps Henderson and his staff who have most embraced the world of social networking. Their Twitter feed is a constant stream of conversation with customers, punctuated with news on menu updates and special appearances. Their Facebook page boasts some 839 "fans" and the Daddy Donkey Appreciation Society a further 500. The former is packed with interactive material: photos from the stall and the kitchen, as well as videos of special events and Henderon's travels. The relationship that Henderson and co have been able to build with their clientele has become one of the business's defining features. Ironically, it took a customer's intervention to kick-start it into existence.

"I was making burritos and this guy asked if he could take my photo," explains Henderson. "I asked him what it was for and he showed me the appreciation society. I couldn't believe it. All these people were on there talking about how much they loved our burritos." Formerly something of an online sceptic, Henderson quickly became a convert, joining in the discussions on guacamole versus sour cream and keeping his Facebook friends up to date with where they would be able to buy their burritos next. Now Daddy Donkey retains a professional social networking expert to help to expand their audience – though Henderson's continued presence on Twitter and Facebook ensures an element of personal interaction remains.

Back at the truck, the benefits of this approach are clear to see. Many of the customers are regulars, familiar with the menu and loyal to their favourites. They banter with the staff as they work, putting in requests for extra fillings and asking them to mark assorted packages with initials so they can distinguish their own choice from their colleagues'. The presence of a my unfamiliar hand in the production line causes amusement more than anything else – the queues here move too fast for impatience to develop.

The result – in spite of the ever-worsening weather – is a kind of convivial, almost carnival, atmosphere. Perhaps this, more than anything, accounts for the sudden success of the food truck. Though Daddy Donkey, Street Kitchen and the rest may be dishing out grub of a higher order, a trip to their van has a certain sense of occasion about it – not a million miles away from a trip to an ice-cream van or – whisper it – the burger truck at your local fun fair. "There is something fundamental about it," reflects Jankel on this pont. "There is a huge amount of nostalgia surrounding the ice cream van – we even considered having out own jingle to play out like they do. People like eating from a truck – though the food served is traditionally so bad that you give people something good and it just blows them away."

Britain's best food trucks

Daddy Donkey

Doling out warming, authentic Mexican food to the masses, Daddy Donkey prides itself on using locallysourced produce from small-scale producers. Renowned for their spicy burritos, no trip to Leather Lane is complete without a visit.

Brewed Boy

Not every coffee cart can claim to offer some of the best cappuccinos in London – but Brewed Boy is the exception. Founded by former journalist and photographer Rob Lockyear, Rupert Street's pavement coffee stand has a loyal following amon g Soho foodies.

The Meat Wagon

First a cult success, then a full-on foodie craze, Yianni Papoutsis's Peckham burger van attracts diners from across the city. This year Papoutsis temporarily set up shop on the first floor of New Cross' Goldsmiths Tavern. The "meateasy" café swifty became a go-to point for carnivores, choc- a-block every day of the week.

Stoats Porridge

Beloved by students at the city's numerous universities, Stoats has been offering early birds a nutritious breakfast since 2004. As well as its delicious organic porridge, Stoats makes a selection of cereals and breakfast bars sold by specialists across Scotland.

La Grotta Ices

Kitty Travers's ice-cream hit the headlines when she was selected as one of 100 chefs to feature in Coco, a round up of the world's brightest culinary stars. Winner of the "Best of the Best" gong at the British Street Food Awards, her flavours range from almond milk to damson, grape and caramelised cobnuts. A regular at foodie festivals, the summertime sees her parked in Maltby Street, Bermondsey.