Welcome to Todmorden: the only town in Britain to attract vegetable tourists. This pretty spot on the Yorkshire/Lancashire border reinvented itself in 2008 with the founding of the volunteer-run community gardening scheme Incredible Edible; six years on, and they're really reaping the rewards. Todmorden is blooming under a very British, get-on-with-it, up-trowels spirit – fruit and veg are growing all over the town (population: 16,000), vandalism is down, spending on local produce is up. And now the rest of the world wants to learn how it's done.

Incredible Edible chair Pam Warhurst has achieved international recognition after delivering a plain-speaking TED talk, and the town's residents conduct regular tours that attract eco-tourists, church groups, people from other councils (and other countries) keen to glean a few green lessons. Prince Charles, naturally, is a fan. I decide to make like Barbara Good, and don my dungarees and Docs to join a community planting day; with me on a tour is a local politician, a group of Leeds University students and a woman who's made a detour on her way from Australia to Spain in order to gather inspiration for new means of sustainable living.

It all started six years ago when one member, Mary Clear, lowered the wall in front of her garden on a street corner in Todmorden. She swapped her rose bushes for herbs, and planted food to share – even if it took a long time to get people used to that idea. Far from greedily picking too much, the real challenge was getting people to help themselves at all; townspeople were worried they'd be seen as light-, rather than green-fingered.

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Then came the guerrilla gardening: Incredible Edible dug up ugly verges littered with dog excrement or equally unattractive spiky council-planted shrubs and put in rosemary, fennel, mint. All without any permission from the powers that be. I'm told by Estelle Brown, tour guide and website-running "granny nerd", however, that they're keen to avoid the term "guerrilla", as it sounds aggressive. "We're a very gentle revolution," she says. "We have 'propaganda gardens' and we have 'accidents' – we fall over with some herbs and they just suddenly take root…"

Much else has taken root, too. There are several official community gardens growing fruit and vegetables, to which anyone is free to help themselves. There's an apothecary garden outside the health centre; Incredible Edible ripped up the boring hardy bushes planted when the new building opened and replaced them with camomile, lavender and echinacea, as well as apple trees. Well, you know what the doctor advises… There are also bobbies on the beets: the police force is one of their most enthusiastic community partners, with raised beds in front of the station (renamed the "Pollination Station"). No fear of getting nicked if you take a lettuce without paying for it here. And whenever local coppers do a raid on cannabis growers, they donate the plant feed, compost and propagators to Incredible Edible.

The benefits go both ways, says Brown: since the sprouting of the movement, the crime figures for vandalism have reduced, and continue to drop. This isn't entirely surprising – there are a few boarded-up buildings, but Todmorden feels like a thriving town that takes pride in itself and how its eco-pioneer status has really put it on the map. And signs of communal green fingers are everywhere: arriving by train, I'm met by pots of herbs on the platform; popping into wholefood-shop-cum-vegetarian-café (what else?), local produce is prominently on sale.

A reporter from this newspaper first visited Todmorden in 2009; four years on, the scheme shows no sign of slowing down. Indeed, two major projects – a farm dedicated to growing sustainable food and training young people, and an aquaponics centre, a collaboration between Incredible Edible and the town's high school, producing vegetables and fish – have become independent limited companies, with paid staff. Education, not surprisingly, is crucial to Incredible Edible's work – growing food is now on the timetable at all six of the local primary schools, while the high school has started offering a B.Tech in agriculture.

And it isn't just the kids: since its inception, Incredible Edible has led volunteer-run classes, demonstrations, food festivals, even Come Dine With Me-style cook-ins to get locals interested. More than 1,000 people have attended informal courses from jam-making to rabbit-skinning. The Incredibles always aimed to reach beyond just the knit-your-own-yoghurt hippie types, and rather than bang on about peak oil or climate change, wanted to make growing and eating local food seem simple, normal and easy. "When people have two jobs and a lot of kids to feed, they have to think fast about food," acknowledges Pam Warhurst. "We need to think about how normal people live their lives, and because they're our neighbours, help them. After six years, we've got people who didn't get it at first, who are now really proud and engaged in this town."

Genuinely changing the culture of a community isn't easy, but it seems as though Todmorden may have cracked it. A town-wide survey run by research students from Sheffield found that around 80 per cent of the residents now buy local produce, while three-quarters grow food in their own gardens. Many also find time to help out at the communal spaces; I met a first-time volunteer, Paulo Marini, who'd popped over from Hebden Bridge because he's such a fan of Incredible Edible's work.

Judy Kendal has been involved for a year-and- a-half: "You put a bit in – but you get so much out!" she declares. Since moving to Todmorden, she's changed the way she shops: "I shop more in the markets, I use the local produce, and I also ask myself, 'Do I need to buy that spinach, or can I go and pick some kale?' You pick it, you go home and cook it, and you eat something that was in the ground an hour before – it just tastes good."

The changes took time, though – as Warhurst is quick to tell others interested in setting up something similar: "If you think it can all be done in a year – it can't. We've got generations disconnected from food. You will not get a return on this within 12 months, but you've got to stick with it and you will see a significant change." Lo and behold, after six years, they seem to have nailed a sustainable, thriving model. I'd bet money on Todmorden still being a hotbed of raised beds in another five, 10, 15 years – but that's because it is, well, bedded in. As Warhurst says, "It's a for ever project: once you start you never stop."

One suspects that even a fleet of bulldozers would have a hard time stopping Warhurst and her fellow Incredibles. The core Incredibles seem to be mostly ladies of a certain age, lots of wafty layered linen and felt hats, but the project also appears to be catnip for the young, eco-conscious, beard-and-dreadlocks latter-day hippie, too.

And Todmorden is exactly the sort of place you'd expect something like this to spring up: rural enough to attract the gardeners and wannabe self-sufficient sorts; moneyed and cultured enough for middle-class do-gooders to have cash to spend on organic veg, and time to spend on worrying about the future of the planet.

But thank God someone is. The really notable thing about the Incredible Edible founders is that they don't just worry: they act. Their "just do it" spirit is remarkable – if only Nike did wellies instead of trainers…

They're also deliciously naughty: as Brown is fond of telling us, repeatedly, they don't ask permission before they plant, because that slows it up, miring a small, simple action in forms and bureaucracy. And, when it comes down to it, nobody really objects to a few cabbages. As long as it doesn't cost them anything, and still looks nice, the council is "good at not looking", she claims. The police chief even begged them not to ask him for permission to plant at the station, because then he'd have to go through his superiors and it might never get the green-light – another indictment of the hands-tied culture of permission so prevalent in many organisations today. Brown has a handy catchphrase for all this: "Ask for forgiveness, not permission." She may have a positively gleeful disregard for officialdom and red tape, but she's still able to speak in soundbites more succulent than home-grown rhubarb.

Warhurst furthers the do-it-yourself argument: "Nobody ever wants to say no to anything – they just can't work out how to say yes. So don't ask them." Quite the firebrand, she's an excellent ambassador for the scheme, a speaker with real passion but also a stereotypically Northern no-nonsense approach. And she has form: now 62, Warhurst has served her time on boards and councils, authorities and trusts, and it proved a very thorough training in how not to get things done. "The time for action is now," she says. "The time to read a report, write a report, make a strategy document, take it to a committee and do bugger-all is long gone. Woe betide anybody who gets in the way of people who actually want to, a) gift to the town their own labour and resources, and b) build a better life for their town. We're just getting on with doing it."

Woe betide, indeed. But the slightly tricky question this attitude raises is: don't you then need an army of hoe-waving zealots to get such a project off the ground? Might the valuable part of the bore-fest that is strategy documents and mission statements and transferable models for action and attainable targets be that they can be rolled out elsewhere, and delivered by other councils or local committees?

Warhurst doesn't think so; she insists that she doesn't want Incredible Edible ever to be a government scheme – politicians are seen as part of the problem, not the solution. The Big Society – of which the Tories would no doubt love to tag Incredible Edible as a prime example – is scoffed at when mentioned during the tour. The whole initiative was founded partly because of a fear that governments just weren't taking the direct, positive action needed in a world going to hell in an increasingly warm handcart: "I thought, 'Well, if no one else is going to do it, we'll do it ourselves,'" says Warhurst. "And it had to be a positive programme – I am bored to death with placards and negativity. I wanted it to be an upbeat, positive agenda, so actually, it was about investing in kindness. Although it sounds like a woolly topic, kindness is at the heart of how we live."

It is an incredibly appealing proposition, and one which has started to spread. More than 50 other towns, particularly across northern England, have taken up the baton. While some don't exactly appear to be thriving – my nearest, Lambeth in south London, has precisely zero forthcoming events on its website – others are really coming into their own. Wilmslow in Cheshire has been another success story; they even managed to persuade a branch of Waitrose to let them plant the very same herbs in beds at the front of the supermarket, for people to take for free, as were being sold inside. Cheeky, and brilliant. And it's not just confined to the UK – Warhurst's schedule currently includes "going to Sweden to give a talk, and I'm just back from Canada, and from Holland. It's time for a brave new world."

It may be quite a slow dawn for that brave new world, and it's hard to shake the fear that unless a community has a Pam or an Estelle or a Mary around to give it a Wellington boot-clad kick up the arse, it may continue to slumber in apathy. But Todmorden is a brilliant example of what can really be achieved with a bit of gumption and some gardening gloves, and proof that from small seeds grow mighty community projects.

But the last word on growing local food must surely go to Warhurst: "It's the only thing we can do to just try to change the future. Which sounds ridiculously ambitious. But why not?"

For more: incredible-edible-todmorden.co.uk