A stench like halitosis from the worst demon in hell threatens to bludgeon everyone out of the room. A cauldron of steaming livers, hearts and lungs disappears into the maw of an industrial mincer and slops out of the other end into a bucket of oatmeal. A crate of beef fat and onion is added to create a glistening mound of carnivore porridge. It is 10am in Braveheart Butchers and flame-haired John Potter has already been up for five hours boiling the ingredients for his Burns Night batch of prize-winning haggis. His rolled-up sleeves reveal a tattoo, "Scotland the Brave", as he plunges his hands into the vat and stirs.
Despite the name of his shop and the words stencilled on his arm, Potter and his haggis are a long way from Scotland. The shop sits on a drizzly high street in the Wirral. Oh, and the tattoo was picked up during a Butlin's holiday in Bognor Regis.
Since he moved to the town of Wallasey, near Liverpool, four years ago, Potter has built up an expanding English following for the puddings, which he makes to a secret recipe. "When I first came down here I thought I'd never have to make haggis again, but now I'm making more than ever," he says, firing up a large square boiler. "I think more haggis is sold south of the border now than in Scotland: I make an 80lb batch every week."
He moved south "for the love of a good woman". His English wife, Michelle, does not, however, extend her affection to sharing his fondness for sheep's pluck. Observing preparations from the relative safety of the shop front she winces at the smells escaping through the fly curtain. "I can't stand it," she says, wrinkling her nose. "It's the skins that are the worst."
A brief inspection of the slimy white sheep stomachs heaped in the sink confirms they are indeed the source of the pervasive rank odour. Potter is undeterred. "It's off-al, that's what it is," he quips, chuckling at his own, rather fetid, joke.
He has been getting used to the smell for the past 24 years. It was then, at the age of 16, that he learned to make haggis as an apprentice at McKirdy's, a family-run butcher in Port Seton. By 1998 his skill had been rewarded with a gold gong at Scotland's national haggis championships. "We put in three of our shops and got first, second and third place," he says, puffing out his aproned chest. "We wiped the board and we held on to that award until 2002."
Scotland's loss is Wallasey's gain. Dora Bennett, 85, one of his regulars, wheels her shopping trolley through the door and picks up her meat for the day. "I'll have a haggis," she says, without pausing for breath. Noticing the posters Potter has put up around the shop, she adds: "Oh, I didn't know it was Burns Night, my daughter just said she fancied it."
Michelle is rushed off her feet wrapping round parcels; customers ask as often for haggis as for cuts of beef or sausages.
Potter says this has become the norm. "I didn't sell a lot of haggis in the first year: I'd put a batch on once in a blue moon. But then word got round that I was a traditional Scottish butcher making this award-winning haggis and the orders started to pour in."
Consulting a list of Burns Night orders for more than 100 people, he pours the haggis mixture into a sausage machine. Sliding a white sheep's stomach on to its spout, he fills it until the intestine's white veins bulge under the weight.
I mutter that the sight is enough to turn anyone vegetarian: using the "v" word around here is a dangerous game. "Vegetarians? They're the scourge of the earth," he growls, before plonking an overflowing fleshy bag on to the worktop.
Preparation is interrupted by another arrival. This time it is not a customer but a delivery from his meat suppliers. A young man in red overalls with a thick Aberdeen accent hands over the hind half of a pig and a crate of beef. "Would you like anything else?" he asks, "We've got some great haggis." John is incandescent. "Haggis?" he roars, "How dare you try and sell me haggis?"
Muttering darkly, he returns to the task in hand. Filling up some 30 stomachs, he pinches each one several times along its length before separating it into fist-sized portions with knots of string. For the chieftain, the larger haggis used for the Burns Night address, he allows a much longer stretch.
A tray of fleshy parcels now complete, he tips them into a boiler. As he begins the mountain of washing-up, his clattering is interrupted by the sound of another customer.
"When's haggis day, then?" a young woman asks Michelle as she collects her shopping. Unfortunately, John has overheard. "Haggis day?" he roars with incredulity, "Haggis day? It's nay haggis day, it's Burrrns Night!"
The Rs are rolled with extra emphasis in mock protest.
So, I inquire, will the proprietor of Braveheart Butchers be celebrating the "honest, sonsie face" of his puddings on Monday night.
His response, dry and deadpan: "Oh, I'll be at home. I haven't dry-cleaned my kilt."