Late one sunny afternoon on a North Yorkshire hill, 40-odd ginger and pink piglets are grunting at me. Being early May, when typically many new lambs, pigs and cows are born, I have come to visit a selection owned by Tim Wilson, the founder of London's Ginger Pig butcher shops.

In recent years, Ginger Pig has fast become the London butcher du jour. If you haven't tried one of its 450 annual butchery classes or bought the odd sausage roll from one of its eight (soon to be nine) shops, you might have eaten Hawksmoor's T-bone steaks, Dishoom's bacon naans, or something from Honest Burgers, as it supplies to around 40 restaurants in the capital.

What I want to know is how this once-tiny business, that specialises in 'high quality, high welfare, native breed meat', continues to do so on a larger scale. Just how does one of London's most fashionable butchers go about its business?

The Ginger Pig story is heartwarming. Having bought a farm with an old pigsty, Wilson, a former antiques dealer, bought a small number of pigs to fill it, including a ginger Tamworth pig he named Dai Bando. Soon proficient in sausage making, he was quickly selling his wares from a stall in Borough Market.

Today Wilson's team rears its own livestock, works with other farms to top up supplies (eg corn-fed chickens from Leicestershire) and will only open shops “where there is local demand. We don't open where there is already a butcher, for example.”

My visit begins at Wilson's original farm in carnivorous heaven, a new cold storage unit. Here only beef – up to ten tonnes including ribs, steaks, and burgers – for Ginger Pig's two biggest restaurant clients, Hawksmoor and Honest Burgers, is prepared, before being loaded onto London delivery trucks.

It's -7˚C, and in front of a row of cow carcasses, three butchers slice off trim from giant racks of ribs and hack up T-bone steaks using a menacing-looking Band Saw machine.

“It's hard work, but all the guys have been working with us for years,” says health and safety manager Andy Woolcott proudly before pointing at a mincer capable of churning up 200kg of meat. “We produce between 2,000 and 3,000 burgers daily.”

Nearby I see inside some vast bacon fridges and an enormous wood smoker. A new room dedicated to sausages, complete with a “real fancy new filler machine, that is worth about £16,000,” is also being fitted out.

“I started making sausages when I was 14 years old, then I left school and have been a butcher ever since,” says Woolcott, who has been employed here for nine years. “We now have ten butchers and three bakers, and if something needs doing, we do it,” he adds.

Smelling something delicious, I peer into a former stable to find sausage roll HQ, where 2,500 are made weekly, along with scotch eggs and seven types of pies.

On one side a man rolls out pastry, and on the other, lard spits furiously inside an open oven, next to which pig's trotters are being boiled up for gelatin in giant saucepans. For lunch we try exceptional freshly made stilton pork pie.

Passionate staff, happy animals, and high standards are clearly key to Ginger Pig's success, but the tough reality of small-scale farming is more complex.

"We probably lose £200,000 a year, and you try and get it to break even but it's very hard," admits Wilson. "I like to do new things but people will not change; you've got to do it, let them see it, and then you've got to provide the market. And people now know we've got the shops in London. Luckily the retail, and the demand for meat, grows pretty much as the supply grows. So that's how you do it."

How does he keep tabs on quality?

"I knew this dairy that made the best cream in the world. But they expanded and the cream [changed]… Years later I met a guy who made tiny sausages himself, and he'd got ten other people doing just that. So that's how you do it. When you want to expand, you try and get other people to do things your way – and that's the difficult bit."

Passionate staff, happy animals, and high standards are clearly key to Ginger Pig's success

It's also about "having an eye for perfection. It's difficult. The whole world wants to cut corners, and it drives you mad. People think they [should] economise for you. But I don't want them to think about that."

Standing amid a mixture of sheep (Blackface mules, Blackface-Leicester crosses, and Texel crosses) and their babies, who baa and bleet loudly, I soon get a sense that this business is focused more on products than numbers.

Inside this lambing shed 500 have already arrived since early April, with 100 to go. Shepherd Ewan Ramage says the flock is slower than usual this year but watching a bundle plop onto the ground before quickly attempting to wobble around is still undoubtedly an endearing process.

Ramage, unlike three of the other handlers Sheryl Edwards, Mel Audsley and Hayley Freers, grew up among sheep and recites lambing rituals to me as if it's second nature.

"We have 700 and I can do them well. It's so much better for me and for the sheep. In my previous job on a really commercial farm, it was hectic. I had 2,000 and if they were lame you couldn't stop to look after them.

It was a real learning curve! Here, though, we could push to 1,000 but I don't want to. Doing it this way, you get better lambs," he explains.

One of Ginger Pig's butchers at work

One of Ginger Pig's butchers at work

It's a similar deal at nearby Blansby Farm (leased by Wilson), where we meet Audsley, equally passionate about her pigs.

"I've been with the pigs for nine months but before I was a prison officer with no experience. It's hard to get into this career, but it's great, they've got so much character!" she laughs, as a group of growing piglets begin furiously snuffling at my boots.

Inside the rearing shed are orange, pink and spotted pigs (Tamworth, Tamworth-Old Spot crosses, Berkshire-Old Spot crosses, Landrace and Tamworth, and Gloucesters) who appear genuinely relaxed and happy. However everything, from the time the boars spend in the pens, to the pregnancy, weaning and rearing phases has to work like clockwork.

The following day, we drive 20 minutes to East Moor Farm (owned by Wilson's cousin) and meet Hayley Freers, a cow handler in her twenties, who introduces us to her favourite Longhorn cows, Maisie, Madge and the great bull, Lohengrin.

"We spend a lot of time with them, and push their hay twice a day. I also like to walk around them a lot so we get used to each other," explains Freers, who began lambing here in 2013. "My first farming job was [here]. I was training to be a vetinary nurse – and then Tim gave me a job, and now I'm with the cows. I do like my cows!"

After a busy morning, I realise it's already 2pm and time to tear myself away and catch the London train. That evening my dinner, a bacon butty made with three of the biggest, plumpest slices of smoked Yorkshire bacon, tastes all the better for knowing its story.