At 6.30am, a large man named Biffo stands outside the Hope pub. His white overalls are smeared in the blood of more than 100 pigs. The shades of red are like splattered timestamps, the darkest dating back to midnight. "I can chop a pig down and cut it up in five minutes," he says, clutching a fresh copy the Sun against his belly. "Legs, shoulders, loins -–all done proper like. It's an art. Chopping a pig down's an art."

As Smithfield Market winds down after a night of dismemberment and meat trade, men in white coats breathe in the still, chilly air as the sun rises above Farringdon. Wholesalers – the ones with clean coats – emerge too, wheeling the last of their purchases towards refrigerated Transit vans. They dodge a few early risers in suits who are on the sober march towards the City.

The blood would elicit gasps in any other part of town. And some coats are grislier than others. "You get bloodier when you're cutting up lambs," explains Biffo, who has the bearing of a retired boxer. (Johnny Griffiths earned his nickname – which he has scrawled on the cloth hat under his cap – because, he says, he knows how to handle himself.) "Lambs you put on a block, and cut towards you. When you do pigs, they're hanging up so you cut away from yourself."

Biffo is 68 and has worked in the market for almost 50 years. At the end of his shift, he's taking a break before the drive home to Chingford in Essex. He gets a coffee from La Forchetta cafe and sandwich bar, and his paper next door at Jasmine Newsagent's. But after a hard night's work as a younger man, in his scrapping days, Biffo would pile straight into the next door along on Cowcross Street: the Hope.

Breakfast at Smithfield Show all 7 1 /7 Breakfast at Smithfield Breakfast at Smithfield Breakfast at Smithfield Biffo,who has worked at Smithfield for nearly 50 years Benjamin McMahon Breakfast at Smithfield Breakfast at Smithfield The Hope pub now caters to night-shifters Benjamin McMahon Breakfast at Smithfield Breakfast at Smithfield Market shoppers enjoy a morning beer with bags of meat, destined for a barbecue Benjamin McMahon Breakfast at Smithfield Breakfast at Smithfield It's not yet 5am and meat is on the move Benjamin McMahon Breakfast at Smithfield Breakfast at Smithfield Taking a break at Smithfield cafe Benjamin McMahon Breakfast at Smithfield Breakfast at Smithfield Smithfield porters with their prime cuts Benjamin McMahon Breakfast at Smithfield Breakfast at Smithfield Tony Woodcock, a regular among the morning crowd at the Fox and Anchor Benjamin McMahon

"You couldn't get in there unless you had a white coat on," he says. "It used to be open all night. And you'd have these rum toddies. You'd get your drink – tea, coffee, beer, whatever – and put rum in it to keep you warm. Cos all these here was open in them days." He points to the sides of the market, which has occupied this site at Farringdon for almost 1,000 years, and in its current form since the 1860s. "It was bloody freezing so all the bummarees would be in here drinking."

"Bummarees" are porters at Smithfield, where a language and culture still clings on at central London's last proper food market. Drink used to be a big part of it. "You'd have blokes pulling big barrows, absolutely legless at four o'clock in the morning," says Richard Sewell. By 5.30am, the meat wholesaler, who is 68 and wears purple tracksuit bottoms under his coat, had already packed up his van before making deliveries on his way home to West Sussex. "But they could get a drink all night here then."

Inside, the last deals of the morning are being done along the avenues that lead off the central market, with its wrought-iron canopy. But on East Poultry Avenue, the Cock Tavern is deserted, and in a sorry state. Through the locked glass door, a dusty sign still advertises "succulent Norfolk turkey" and "whole Lancashire poussin". Once an integral part of the market, the pub has been shut since 2010, the victim of big change for a community steeped in blood and tradition.

"You've taken the humour out of the market," Sewell says in the seat of his van. "You used to go down there and it was all open with shouting and balling and it was just funny all the time. I can recall a right old snob coming down, being shown round the place. A Labour MP I think. He was ignoring all the staff so somebody got hold of a sheep's eye and chucked it at him. Got him right on the back of the neck. The place was in uproar."

It's not yet 5am and meat is on the move (Benjamin McMahon)

Smithfield isn't so much an open market these days as rows of butchers' shops fronting sealed refrigeration units. Traders blame health and safety laws for chopping up the atmosphere, as well as drink-drive laws and the London congestion charge, which kicks in at 7am. Shifts are earlier than they used to be, and while butchers and porters once lived in London, and staggered home, they now commute to Essex, Kent and beyond. It means that only a vanishing fraction of the old boozing crowd can take the time or risk to have a drink.

"A lot of these blokes have been up since nine last night, to get in here and start their work," says Robert Marriott. The butcher was vaping on a bench outside the Hope with a cup of Pret A Manger tea when Biffo walked past. ("Here's an old lag, he'll talk to you," he had said.) "At the end of your shift, your body is just knackered," he adds, turning to the pub. "By this time it used to be really busy out here, now it never picks up."

Only the meat is the same at Smithfield, an island of working-class tradition slowly sinking in a gentrifying sea of luxury apartments, restaurants and nightclubs. Cultures clash on several fronts: traders of meat against money, and everyone against the clubbers who spill into the streets on a Monday morning. Fabric, now a London institution with a vibrating dancefloor, opened in 1999 inside the old Metropolitan Cold Stores. "You see 'em shagging up the wall and all sorts," Biffo says. "That's a toilet there." He points to what looks like a manhole cover outside the Hope. It rises up at weekends to reveal urinals. "You get women just squatting there, pissing."

Biffo has a dim view of young people, including the new butchers. "Once us old 'uns go, it'll be stone dead in there," he says. "This generation, all they want to do is put gear up their nose." Jake Quirk is 22 and is waiting outside La Forcehtta for his mate to buy him a sausage roll. His white coat suggests he has been cutting lambs tonight, or "busting them down to their primals," as he puts it. "The two of us have done about 200. I'm going home to bed now." Soon his colleague emerges with a drink, a can of San Pellegrino aranciata rossa (the blood orange one). Bit of a posh choice? "Well I'm a man of leisure, ain't I," he says, walking to his car for the drive home.

Taking a break at Smithfield cafe (Benjamin McMahon)

If they weren't at the Hope or the Cock, white coats used to fill the Rising Sun, the Old Red Cow, or one of the many market pubs that no longer exist. The Smithfield Tavern, which lately offered – boldly, perhaps – a vegetarian-only menu, got boarded up just weeks ago. Many of the surviving establishments still have exceptional licensing hours, granted to them when market life was different. But only two proper pubs use them: the Hope and the Fox and Anchor. Today, neither pub attracts market traders, yet booze flows at both. Who is drinking it?

At 6am, Alex, a Romanian barman who has lived in Britain for six years, opens the doors of the Hope and pulls perhaps London's earliest pints. Joe Saxton and Craig Jarvis are scaffolders coming off a night shift at the new Crossrail station at Farringdon. "At most we'll have about 12 of us on a Friday, just a little drink after work with the lads," says Saxton, who is 36 and from Chesterfield. He sees no shame in sitting outside with a pint. "Now is like six o'clock in the evening for us," he says. "And because of the market it's an accepted thing around here." Most drinkers here are night-shifters. Later, Crossrail construction workers sit next to three young police constables who have come down from Hertfordshire for a pint "or three – we'll see how we go".

The atmosphere is as convivial and fuzzy as it will be 12 hours from now. Two men hold halves of Stella, their second round. Plastic bags of meat (beef ribs, pork chops, a leg of lamb and an oxtail) rest at their feet, destined for a weekend barbecue. Some drinkers are wary of talking, perhaps not keen to dwell on their reasons for being here. A man sitting alone at the bar, staring ahead with his pint, flinches in response to the mildest inquiry.

Market shoppers enjoy a morning beer with bags of meat, destined for a barbecue (Benjamin McMahon)

About 100 paces along the road, next to a newly-opened gay nightclub called Fitladz ("Fitladz is for Fitladz who like Fitladz," its website explains. It used to be a cocktail bar called Tart), the Fox and Anchor has been serving out-of-hours booze for centuries. It now opens at seven but it's not until 7.32 that Sam Ruane pulls the first pint. The early hours suit the 24-year-old actor from Bakewell, because he can go to auditions in the afternoon. He recently bagged a role as a love interest in Hollyoaks.

Even in the year that he has worked here, Ruane says a tiny amount of market custom has all but dried up. If the Hope now caters to night-shifters, the more expensive Fox, which offers boutique rooms upstairs, serves mainly city workers. The menu is famous for its City Boy Breakfast. For £16.95, hungry money men can eat two eggs, bacon, two sausages, minute steak, lamb kidney, calves' liver, black and white pudding, tomato, mushroom, beans, fried bread and "a pint of stout to finish".

No one is brave enough for the plated farmyard today, and City trade never builds. The first pints go to Ben Shepherd and Richard Winwright, who have just spent 12 hours fixing stairs as part of London Underground's escalator response team. "Thinking about this got us through the shift," Shepherd, who's 25, says. "Three more hours and we could have a pint." They order the relatively modest Full Monty with a pint of Young's Special. "I haven't had a drink this early outside an airport," Winwright, 28, says.

The men will order their second pints half an hour later, and then call it a morning. But the City crowd often goes much further, showing little of the restraint now displayed by the men who built this place on the backs of a very different commodity. "Some of the groups that come in on a Friday, you look at them and think, where did my life go wrong," Ruane says. "They go out on Thursday night, come in here at eight, hungover, and have their bloody mary and stouts, then at 11 they'll check some emails, close a deal or something – pissed out their heads – then come back in for lunch. What a life!"

Tony Woodcock, a regular among the morning crowd at the Fox and Anchor (Benjamin McMahon)

Ruane is endlessly entertained by the dynamics of the invariably all-male city groups who fill the Victorian booths at the back of the pub. "It's hilarious, because everyone thinks they're different. But I go up to every single table and say, 'can I get you any drinks to start with?' They're all like, right, yeah, coffee, tea, coffee, tea. Then the chief exec will go, 'yeah, I'll have a stout actually'. Then, one by one, they'll change their orders. They're just waiting for the nod of approval and – bang – they're in."

While things are quiet, Ruane suggests skipping across the market to St Bart's Brewery, a modern pub in the grand premises of a forgotten bank. It used to open at seven, then eight, but a cleaner washing down the front steps says it now doesn't open till 11. It's the same story in the passages around St Bartholomew's, a flint church that has served worshippers here since the 12th century, when farmers would still herd their livestock to the "smooth field" that became the market.

Further along, Bird of Smithfield – a restaurant and bar painted a glossy black with gold lettering – has been open since 7.30. Inside, Jason Nicoli, an actor and the proprietor's husband, is serving breakfasts to office workers. His licence means he can sell alcohol from 5.30am all the way round to 3am, if there were money in it. Everyone's on the coffee this morning, "but I've served quite a few drinks this week," Nicoli says. "There's a couple who live in the the Barbican who come down for champagne breakfast, then it's your city people having a pint early doors."

Nicoli has Italian heritage and has cornered the market in corny voice-over work. Most notably, he plays Carlo, the son of the puppet family in the Dolmio TV ads. "Mamma! Is today the day? Make thees a Dolmio day!" He delivers his line while wiping down menus, not stopping even as he answers the phone behind the bar. "Theesa lasagne is eeven bayter than before- hello, Bird of Smithfield?" Nicoli rarely sees market people through the door, but reveals that, no more than once a month, a group of master butchers books the private dining room upstairs "for a proper piss-up… They all have black pudding sandwiches and scrambled eggs with Peroni, and watch Jeremy Kyle on the projector."

Trade is still slow back at the Fox & Anchor, but an older man has taken a seat inside the entrance, where Ruane has opened the doors to welcome the warming morning. Tony Woodcock is a brother at The Charterhouse, a former monastery established in the 14th century on a Black Death burial ground. Now an almshouse, it is home to dozens of retired men. Woodcock, who is 74 and originally a window dresser, got in because he used to be a butler to the Lord Mayor of London. After that, he worked for a contessa in Miami. "That was fun, but she was a bitch, an absolute cow," he says, holding a glass of pinot grigio next to his copy of The Lady magazine.

Smithfield porters with their prime cuts (Benjamin McMahon)

As Tony de Mars, using his mother's maiden name, Woodcock, who cannot stop smiling, makes ornamental masks in a shared studio in The Charterhouse. But when the sun rises early and it's warm, he has taken to starting the day here in solitude, to reflect with a glass of wine. He pulls out his business card, and produces some photographs of his mother, and of the love of his life – Carlos Douglas, an actor who played the camp waiter in the hit 1980s sitcom, Duty Free. He died 10 years ago. "I don't usually drink in the morning, but this is my world now, and I can see what's going on and who's passing by," Woodcock says. "And if it's the master of Charterhouse, I hide behind my magazine."

A local cat has started to visit Woodcock at the pub. He calls it Pyewacket, after the cat that Kim Novak, playing a modern-day witch in Manhattan, used to cast a spell over James Stewart in the 1958 rom-com, Bell, Book and Candle. "I like it here," he adds. "I hate to say it but I haven't got much longer on this planet, you see, so I just want to enjoy my life as best I can." Will he stick to the one glass? "Do you mean you'll buy me another?" he cackles. "What a charming gentleman. But, no, just the one glass."