'Yes! We have no bananas' may be the title of a 1920s song, but it could just as easily apply to Beverley and Luke Randall's Eastbourne store. Walk into Local Roots & Wellie Boots and you are greeted by a smorgasbord of the fresh and delicious. 'Look at it,' Beverley says. 'It's like a harvest festival.' Baskets brim with leafy cos lettuce, emerald spinach, knotty kohlrabi and exotic purple French beans. An old metal bucket holds a thicket of pink rhubarb, flanked by mounds of gleaming redcurrants, cherries and strawberries. What you won't find, though, is bananas. Or lemons. Or pineapple, for that matter. 'We only stock produce that is British and seasonal,' says Luke.

A great idea, but what makes the shop special is that the Randalls not only obtain stock from small farmers but also take crops from local gardeners and allotment holders. 'People growing their own always have surplus,' Beverley explains. 'You can only pickle and give away so much.' The produce is bought and sold at a fixed price: 50p per item/bunch or per kilo, sold on at £1 per item or kilo. 'It's to prevent people growing all one crop because it fetches a preferential rate,' explains Bev. But rather than take payment in cash, these small growers are encouraged to swap their harvest for something else in the shop. Why? 'It gets people tasting all this lovely local produce,' Beverley continues. 'They might pick up some local jam instead of buying a branded version. It opens their minds a little.'

Liza Brown is one customer keen to swap. With a bumper crop of courgettes, salads and beans in her cottage garden in East Dean, a village a few miles west of Eastbourne, she plans to bring in something most weeks. 'I'm only interested in swapping though. I like the ethical side of it.' Currently some 20 people bring in their excess, but in the future they would like a quarter of all fresh food to have been grown in this informal, small-scale way.

Dismay at the air miles accrued by so much produce was the incentive for championing local fare. 'I wanted onions one day,' remembers Luke, 'and in the supermarket they were all from New Zealand. It drove me mad. Why are we importing onions when they grow perfectly well here?'

Now the couple buys produce from 77 suppliers around the region, including tomatoes from Alfriston, water from a spring near Uckfield and marmalades from Plumpton. Everything, from the milk and cheese to the pasta, pickles and jams, is grown, made or sourced locally. And while Bev and Luke like their produce to be organic, it's more important that it comes from the area. As the majority of suppliers are very small, Luke collects much of the produce himself each day, starting with a 7am bread pick-up in the car park of Seven Sisters Country Park, a local beauty spot and convenient midpoint between the baker's home and Eastbourne.

Once back at the shop, Beverley displays the range. While meat and game is frozen and the bacon, sausages, cheese and unpasteurised milk refrigerated, the fresh fruit and vegetables are not because it dilutes their flavour. They are instead arranged on two central tables, and only packaged where essential. Stock is misted with water to keep it fresh and is never displayed for more than two days when any surplus becomes the soups, summer punches and smoothies on sale in the shop's cafe. The couple's family - they have a two-year-old together while Beverley has four children by a previous relationship - scoop up whatever's left. Finally, the skin and peelings are used by a local fruit farmer to make compost.

The shop has grown as rampantly as the fresh produce sold inside, but began life as a small-scale sideline. After leaving London for Eastbourne in 2006, Bev and Luke opened a second-hand furniture shop. When the tiny premises next door became available, they leased it, unsure at first how to use it, but after chatting to the farmer who supplied their weekly veg box hit upon the idea of selling her surplus there. 'We said, we'll take whatever you have - a sack of potatoes, a few carrots,' says Bev. 'It's quite funny looking back.'

Passing Buys, as it was then called, was an instant success. 'We were only a few steps from Waitrose, but we had queues out the door,' says Luke. The idea grew so quickly that the Randalls soon wound up the furniture store and in November 2008 moved to their bigger, more central premises, a short hop from the station. 'People like the quality and taste,' says Luke. 'Elderly customers say things taste like they used to.' Joyce Adlington defnitely agrees. 'I really appreciate what they are doing here,' she says. 'I like that it's all local. You can taste the difference.'

Watching Bev and Luke at work, greeting customers - they know 75% of them - sharing recipe ideas and passing on their knowledge of exactly where each tomato was grown or which breed of hen, eating what diet, laid the eggs, you realise there is more than simply quality produce to the success of Local Roots. The couple has harnessed the national interest in shopping locally and eating well, but teamed it with a genuine passion for what they sell and a traditional, down-to-earth approach, that prioritises friendly service.

There's a family-run feel to the shop. One or both of the Randalls is always there and Bev's oldest children, Bella and Jack, cook and serve the meals. They are happy to sell a single tomato or halve a cucumber for a customer and will deliver shopping for a modest 50p. Cafe customers can choose any of the jams on the shelves for their morning toast ('blackcurrant curd is a favourite,' says Bev) while those who use the veg box scheme can vary its contents each week. 'Just ring and say I don't need potatoes and we'll put something else in,' says Luke. 'It's a return to the village shop idea,' adds Bev. 'We want shopping to be a nice experience, not a chore.'

Of course, all this service and freshness would count for little if it came at too great a price, but the Randalls are committed to making quality food affordable, not just available. 'We have asked ourselves how can we compete against supermarkets, but we can beat them ethically and on price,' says Bev. So outside, a cost comparison board reminds shoppers that today, their eggs, strawberries and artichokes are cheaper than at the larger competitors.

Running Local Roots is a far cry from Bev and Luke's former jobs as teachers (although they do sell produce grown by students at the local college) and their gastronomically spartan childhoods. 'My mother hated cooking and we don't come from grocer families, but now we've turned full circle and become obsessive about good food,' says Bev. Brimming with passion and commitment - these two don't take holidays - they are keen to spread the word about the benefits of shopping locally, taking part in a Live Better For Less exhibition in 2008 and advising the local council on stockists for the now monthly farmers' market, founded in April 2009. Most of all, though, they would like to see the Local Roots model spread. 'We'd love other similar shops to open around the country,' says Bev. 'If we have done it from nowhere with no experience, anyone can!'