In a tiny, windowless back office, Dan Ebdon is hunched over a computer screen. “I’m trying to find a Victorian-style ash pan,” he says. “But I’m struggling.”

His knees are pressed against rolls of black bin liners, the shelves at his elbow hold drums of cable and chain, and hanging overhead are racks of wood mouldings, all part of this hardware shop’s 25,000 products. “I must have spent an hour on this,” he sighs.

The supply of fireplace ash pans may not seem like a vital trade issue in the Brexit process, but on Bishopthorpe Road in York, a high street populated by small independent retailers such as Ebdon’s Pextons Hardware, supply chains are a big concern right now. “Our reputation is all about having everything,” he says. He stacks the types of product that he is having trouble sourcing on the sales counter outside the office, topping the pile with four fork handles. He grins. “Remember the classic Two Ronnies sketch?”

I do. That’s the one in which they brilliantly lampoon the hardware shop that stocks everything. “Well, it’s no joke: fork handles, brushes, kindling, some household chemicals, you name it. I can’t get budget sacks of charcoal, for example: larger buyers are stockpiling and we don’t get a look-in.”

A customer comes in asking for a special type of lightbulb. Dan tracks one down in seconds. “We rarely admit defeat,” he says. “But smaller suppliers are demanding larger orders, or imposing currency surcharges. One of them simply stopped answering the phone. In the end, I rang a business next door and asked them to take a look. They said the place was empty. The owners had closed down and disappeared.”

Here, you get a sense of how damaging the impending Brexit storm might be and how individual lives are already being hit. In March last year, I visited this same street, known to locals as Bishy Road, and found a bustling retail centre that had bucked the downward trend for high streets by sticking with local independent shopkeepers and cultivating deep roots within the community. The thirst for such beacons of retail hope was obvious. Councils and trade bodies from all over Britain have visited to study the Bishy Road model. French television came and filmed. But how is the success story holding up? Can Bishy Road, and other similar streets, survive the disruption that Brexit is already causing – and that might well turn to chaos in the event of a no-deal EU exit?

In central York, the boarded-up shops are conspicuous – all the more shocking when you consider that tourists spend more than £500m in the city each year. Other towns and cities don’t have that financial cushion. Even the retail flagship, Coney Street, looks forlorn. And over in the historic street Pavement, one of the country’s most beautiful shop buildings, a 16th-century timbered mansion, lies empty, unable to hang on to its last occupants, a cancer charity. This particular mansion is filled with the ghosts of old social divisions: former occupant Thomas Herbert was knighted by Cromwell, switched sides during the civil war, and lifted a title from Charles II. In every national crisis, as Herbert could have told you, there will always be winners and losers.

Back in Bishopthorpe Road, the only obvious loser at the moment is Domino’s Pizza, which closed a few weeks ago. But how are the independents doing? I visit Setting the Scene, where florist Richard Bothamley is sorting through some new deliveries. “We get the best flowers, top quality, mostly from Holland. Look at these oriental lilies: there’s only one Dutch horticulturalist producing flowers as good as this.”

Bothamley studied with Alan Titchmarsh, worked at Edinburgh’s botanical gardens and now supplies flowers to local luminaries such as the fashion designer Matty Bovan. “What I like here is the community,” Bothamley tells me. “Loyal local customers, whether they’re spending three quid or a hundred.” He and his partner Glenn Hamilton opened in 2012 in a tiny corner shop that, in Victorian times, was Charlie Pinder’s pianoforte and beer shop (presumably Charlie focused more on beer than pianos, given space constraints).

A customer comes in wanting an orchid as a leaving present. Bothamley turns to give detailed advice on how to keep the plant going. “When the flowers die, trim it hard, leaving some buds. It’ll come back stronger.”

Is that what Brexit will do to our high streets?

He shakes his head. “It could be terrible for us. Ordering and delivering within 24 hours will not be possible. I worry the flower business will go online and never come back,” he says. “And, personally, I won’t go there.”

Bothamley’s Dutch suppliers are worried, too, he tells me, adding that Holland is a world centre for the flower trade. “They can manage without us.” He needs them, however. We look around the shop; even the South African proteas come via the Netherlands. There is one jug of daffodils from Lincolnshire. “People don’t like the air miles, but it’s a global business. Practically every carnation on sale comes from Colombia. Those roses are Italian.”

He has a photo of David Cameron giving a speech over a floral display that the shop produced back in 2012. “Cameron cut business rates for small places like us. We thank him for that, but not for Brexit.”

A regular customer comes in: Florencia Clifford, who owns Partisan, a restaurant in York’s Micklegate – another independent high street. Micklegate learned from Bishy Road, successfully adapting its model of holding street parties and events. It is also a road that has witnessed many crucial moments in the long and splendid tradition of British acrimony. Here, in 1644, a battered royalist army surrendered to parliament’s forces, heralding the end of the civil war. And here, in 1486, Henry VII paraded in triumph a year after the battle of Bosworth, the last act in the Wars of the Roses. Clifford, however, is more interested in the current national division. “I want to invest but I can’t. Some of my suppliers are saying that price lists are just for ‘guidance’. How can I plan? I don’t want to simply raise prices and be exclusive.”

Is she stocking up on anything? She laughs: “I don’t have space. But I am buying all sorts of exotic treats. Who knows if we’ll still be able to get them?”

Bothamley wraps up one such exotic treat for her: an armful of white amaryllis. “My kind of restaurant depends on being part of the world,” says Clifford. “I don’t want things to go back to how they were 25 years ago, one type of limp lettuce available. I like the variety of fruit and vegetables that I can get now.”

As she leaves the shop, she admits that the uncertainty is causing a lot of stress. “I’m anxious. Running a business is hard, but Brexit has made it harder.”

The negative health effects of uncertainty are a worry for many people. A few doors down from Bothamley, pharmacist Josh Carter is fielding plenty of inquiries about Brexit and drug supplies. “People are concerned about getting their medicines, especially things like insulin.”

In recent weeks, he says, the number of drugs with supply problems has jumped from a “normal” rate of around 20 to 80. “And these are widely prescribed medicines that we deal with on a daily basis, things that we’ve stocked for years without a snag.”

Whether this is because of Brexit is impossible to know, Carter says, since the pharmaceutical market is highly complex. British manufacturers even export to other European countries, only to reimport for sale here. Government advice remains not to stockpile.

I call Arnold Warneken, a local organic grower, who also chairs patient groups for two local GP practices. “I look at Theresa May and see the stress on her, and I think, ‘Is it worth it, Theresa? Just to become a baroness?’ But, seriously, the impact on small businesses is disproportionately high and all that stress means the effect of Brexit on the NHS is huge.”

He has had staff leave his business, Goosemoor Organics, because the recent job insecurity was too stressful. “They have mortgages. They need stability and I can’t plan for the future.”

For Warneken, the trouble started on the night of the referendum. “We supplement with produce from France and Italy. Immediately after the vote I lost £4,000 from depreciation of the pound. Since then, I’ve watched our supply chains thin out and our market access decrease.”

Like everyone I speak to, he believes steep price increases and supply problems are inevitable, especially in the organic market. “Butternut squash, for example, cannot be grown organically in the UK. I’m hoping prices don’t rise by more than 40%. Nectarines and peaches from Italy could be problematic – even a few hours more on the truck will decrease shelf life.”

Warneken is also pessimistic for the independent high street. “I think places like Bishy Road will be a thing of the past. That’s a tragedy.”

On Bishy Road itself, no one is entertaining that gloomy prognosis, but not everyone wants to talk Brexit. Some traders refuse to discuss it. York was a remainer town, but some customers may be Leavers. In a small community, it is sensible not to alienate anyone. The newest shop on the street is the Bishy Weigh, started up by local entrepreneur and cake-maker Alice Hildred. It opened in December. “I was doing a plastic clean-up on Bridlington beach and decided I needed to do more.”

The result is an “eco pantry”, where customers bring containers and fill up with everything from pasta and olive oil to washing-up liquid and shampoo. “I’m not feeling any Brexit problems,” says Hildred brightly as she faces a queue of customers. “There are bigger things to think about, aren’t there? For me, the environment is more important. We make our own almond milk and peanut butter. We sell honey from the allotments up the road. I’m hoping we can get a delivery scheme together for all the shops.”

Her venture, and positivity, has brought a new, younger type of shopper into the high street, one who would rather focus on environmental concerns than Brexit fears. Other shops are on the same wavelength: greengrocer Frutique has replaced plastic bags with paper bags. Millie’s, also a greengrocer, has started vegetable box deliveries of local produce, while butcher M&K sells meat from three local farms. These are people who tackle problems and shrug off difficulties.

In the centre of Bishy Road is Trinacria, a Sicilian restaurant and cafe owned and run by Beppe Lombardo. I find him putting in extra orders for Italian ice-cream products: “cones, flavours, chocolate, and plenty of tubs and spoons”. Despite the stockpiling, he, too, is upbeat. “I buy a lot from Italy and those suppliers are putting up their prices already. They slapped 5% on just because of the leave vote. Now they’re adding another 10. But we’ve had a great year and I expect another good one.”

He is opening a new venture, supplying food to the Crescent, a working men’s club turned music venue, and is mulling over an idea for a city centre ice-cream parlour.

Is this kind of optimism justified? Andrew Goodacre of the British Independent Retailers Association, a regular visitor to the city, certainly thinks so. “Our members are used to rolling up their sleeves and getting on with it. They know the value of good relationships with staff and customers. They find interesting products, things people want, and they do business with style, even a bit of theatre.”

The sense of pragmatic optimism extends outwards from Bishopthorpe Road. Caroline Barugh, once a local primary teacher and allotment holder, began Goodness Farm on seven acres of borrowed land in 2009, selling vegetable boxes. She believes the local food movement might be helped by Brexit. “We fill our veg boxes every week of the year with things grown here.” She lists what is going in this week: cabbages, leeks, broccoli, chard and herbs, plus carrots and spuds from the farm next door.

Across the fields from Barugh’s smallholding rise the ruined towers of Sheriff Hutton castle. As I go to explore, I fall into conversation with a passerby, who assures me: “The Normans built it and Cromwell knocked it down.”

I smile wryly. So European interlopers built a mighty structure, which a civil war then destroyed?

Except that this turns out to be incorrect. The castle was built by an Anglo-Saxon family, the Bulmers, who had made peace with the Normans. Cromwell never went there. It was a ruin before the war. Beware alleged historical parallels.

A couple of days later, I pop back into Pextons and find that Dan Ebdon has cheered up. He shows me the Victorian ash pan he has found. “There’s a guy in Staffordshire making them. I hope that customer comes back for it.”