A new generation of shipbuilders has found a home on the Clyde

• Lyn Gordon, 23, is into her second year as an apprentice fabricator

Follow this wall and you come to a three-storey red sandstone building, constructed in 1890, but lying empty and boarded-up for the last decade.

The main entrance is secured by a steel door covered in graffiti scrawls, but there's no mistaking its grandeur even now: flanked by statues of a shipwright and an engineer; topped by a brace of mermaids and a bust of Neptune.

This is the old Fairfield building, once the headquarters of the most prestigious shipbuilding business in the world.

The impression from outside is of dereliction and decay, a sad relic of a proud past, but do not be fooled. Behind this building and behind the wall, men – and even some women these days – still build ships.

The BAE Systems yards here and across the Clyde in Scotstoun employ around 3,700 people and, as the last remaining shipyards in Glasgow, represent a rich living history, the embodiment in brawn, sinew and technological know-how of a tradition that is a key part of west of Scotland identity.

"I was born to be here," the workers will tell you. "It's in my bloodstream."

Glasgow's shipyards are part of the city's creation myth. As Eden and Canaan are to Christianity, so Govan and Scotstoun are to Glaswegianity.

So much of the west of Scotland identity comes from the yards: the hard man, the big man, the tough wee man; the drinker, the grafter, the joker; the left-winger, the right moaner, the maker of things; kindness, too, and thrawnness, and the ability to thole.

Thole not dole, that might be the motto of the shipyards; better to endure the punishing physicality and economic uncertainty of the job than suffer forced idleness. And that word "ship", it's in so much of what the yards are about – comradeship, craftsmanship and sometimes hardship.

The yards are not just a workplace, they are a repository of identity, a great flooded dock brimming with shared attitudes, values and history.

Shared achievement, too. "There's been a lot of tough times through the years and I've been here for 32 of them," says Andrew Watson, a 48-year-old welder known as Winker.

"We've seen guys come, guys go, but we're still here building ships. We're the best at whit we dae."

The first shipyard in Glasgow was established in the early 19th century at Stobcross, on the north side of the river, where the Finnieston crane is now.

Ships were built in wood and later iron. Steel came in around 1880. By 1913, more than 100,000 people were working in 38 shipyards and ancillary industries strung along the river like black pearls; more than half the world's shipbuilding production took place in Glasgow, and "Clydebuilt" became a stamp of quality, recognised internationally.

The word resonates even now when Japan and South Korea have replaced the UK as the world's great shipbuilding centres, and has come to denote strength and integrity; when the great trade union leader Jimmy Reid died last year, Alex Salmond described him as Clydebuilt.

On a cold, grey February day, BAE's Govan yard presents a grand spectacle. From 23 metres up, on top of the Queen Elizabeth aircraft carrier being built within a gigantic, hangar-like space, you can look out past the giant cranes and north across the Clyde to riverside ziggurats of luxury flats, the red- terraced tenements of Broomhill, and beyond the city to the snow-cloaked Kilpatrick Braes.

Shipbuilders work at all hours in all weathers. The great halls known as sheds where the ships are built face on to the river and are open to the elements.

This winter it got down to -15C, and there were sheets of ice in the water as thick as the steel in the yards, but the job went on. Welders working the night shift resembled silverback gorillas: the frost came down overnight and covered the backs of their overalls; bent over the hot torch, their fronts remained clear.

"Hard as nails, so we are," says Stuart Gray, the 36-year-old supervisor of the fabrication shop. "Does the cold bother you? Yes it does, but by Christ it makes you hard. I think the Clyde gives you a new immune system."

It is at desolate moments like that when the well-known shipyard sense of humour comes into play. A belly laugh can warm you better than a cup of tea. The most famous exponent of that particular strain of humour, of course, is Billy Connolly, who worked in the Clyde shipyards in the 1960s.

"Billy Connolly?" says Gray. "That guy owes us money. He was a shite welder, but he took note of the patter. This is where he got it from."

The fabrication shop, known as the fab shop, contains the panel line, known as the penal colony. The standard joke among the older workers, who have been here for decades, is: "Ah'd huv been oot quicker fur murder."

The panel line is where ships begin. Here, plates of steel measuring 12 metres by two are welded together, using a large machine called the seamer, into enormous sections of deck and hull. It is oxyacetylene couture.

It is easy to feel dwarfed in a shipyard. Everything is on a grand scale. Perhaps in order to stand out amid this vastness, many of the workers have vivid personalities. Take 55-year-old Alex Stewart.

"What can I tell you?" he says. "Everybody knows me as The Singing Plater."

He then goes on to show why, performing – to the tune of Kenneth McKellar's the Song Of The Clyde – one of his own compositions, which concludes: "Oh, it fills you with pride to work on the Clyde/The name BAE Systems is known worldwide/And I'm proud to say, whoever you are/Our aircraft carriers are the best by far." Wiping the dirt from his forehead, he goes back to work.

"This is such a big, cosmopolitan place with every type of person," says Jamie Webster, the GMB union convenor.

"A lot of people on the shop floor are amazing. You might think they are just ordinary craftsmen, but some are very clever. You wonder why they work in the shipyard, but you realise they made that choice. There's a lot of folk who just like a simple working life. You get welders interested in photography or archaeology.

"I remember I met this auld labouring man. I never met anybody as articulate and intelligent in my life. He had a kaleidoscope of knowledge, but he was quite happy labouring. There's confusion about what ambition means. A lot of folk think it means you always go up the way in life, but I've learned that sometimes the ultimate ambition is just being happy. So you almost get a philosophical education just by being here."

Nicknames are common among the workers. Winker, Skippy, The Singing Plater, Lazer Dave. Formality is a no-no. Woe betide the incomer who addresses a worker as Mr or, worse, sir. "Ma name's Wullie," you'll be told. "You're in a shipyard, noo."

The lingua franca is the kid-on put-down. Bad language is rife, but not when women are near. An old-fashioned chivalry persists in matters of that sort. Doors are held open for female members of staff.

Not that there are many of those, at least not in the yards. One young woman says that, of the 70 apprentices taken on at the same time as her, only three were female.

Lyn Gordon, a 23-year-old now in her second year as an apprentice fabricator, explains the appeal of the shipyards. "Better than hairdressing," she laughs.

"Nah, I prefer a bit of hands-on work, up to my eyeballs in dirt and grease. Just what every other lassie wants really."

In fact, growing up in Greenock, she was enchanted by the sight of ships and takes great pleasure and pride in the fact that she now builds them.

"It's all about heritage, isn't it? It all leads back. That I'm still working in a surviving shipyard in the Clyde is quite a big deal. To be able to say I'm part of it is pretty good. You get to gloat a wee bit."

Despite the fact that shipbuilding in Scotland has been in decline for years, this sense of tradition seems attractive to young people. Alan Morris, 24, is a design engineer working on the early stages of the Type 26 global combat ship. An ambitious young professional, he speaks the language of high-spec engineering and complex computer-modelling, but does not lack appreciation of the roots of his industry.

"Shipbuilding has been the lifeblood of the city," he says. "My grandfather was a sheet-metal worker on the ships. My great-grandfather was a riveter. A lot of people seem to think shipbuilding is dead, but it is still alive on the Clyde."

Morris works in the Scotstoun yard, where work is continuing on the remaining three Type 45 destroyers which BAE has built for the Royal Navy.

To spend time on board one of these ships – the HMS Dragon – is to understand that modern shipbuilding is about much more than shaping steel. Dragon has been fitted with a complex weapons system.

"This is you in the combat zone; this is the ops room," says Brian Carson, the 48-year-old combat system manager, who began here as an apprentice electrician at the age of 16. He points out the various features of the ship's operations room – a long, low, dim space with a new-car smell – including the "soft-kill" area from which decoys are launched in order to "seduce" hostile missiles away from Dragon.

The ship has been fitted with powerful radars which rise from the deck like a pagoda and a minaret. From near the top of the main mast sprout a number of conical structures, known as Madonna's tits, which are also part of the radar system.

Even the most committed technophobe and pacifist would find it difficult not to be impressed by this cutting-edge killing machine. These shipyards have long been at the forefront of naval technology. In 1861, Robert Napier's Govan yard built The Black Prince, one of the early iron-clad battleships.

It was Napier who gave a start to John Elder, the genius inventor of the compound engine, who established the business in Govan now owned by BAE. Over the years, the yard has changed hands many times.

Shipbuilding firms tend to have genealogies which rival the Old Testament for complexity. Elder's begat Fairfield's begat UCS begat Kvaerner begat Marconi begat BAE. Sometimes the old names persist. BAE's Scotstoun yard is still known throughout Glasgow as Yarrow's.

There is a tremendous sense within the shipyards of the past breaking the surface of the present. This is formalised in the apprenticeship schemes in which the experienced workers pass on their skills to youngsters, having themselves been taught by the skilled craftsmen of their own day, and so on back to the birth of the industry.

Thus an apprentice using a burner to cut steel today could trace a line back to a shipbuilder sawing wood at the Clyde's first shipyard, Scott's of Greenock, in the early 18th century. It is the industrial equivalent of the army's so-called golden thread.

BAE's present project is the construction of two aircraft carriers, the Queen Elizabeth and Prince of Wales. Work began in the summer of 2009 and is due to finish in 2014 at a cost of 4.8 billion.

Each will weigh 65,000 tonnes when complete and will dwarf the largest aircraft carriers in current use. Standing at the foot of the partially built carrier, you have to crane your neck to see the top.

It does not look like a ship; more like a skyscraper in embryo. The word "aft" has been painted on to the appropriate side of the hull, and it is gratifying to note that some joker has prefixed the letter "d".

That says it all about the Clyde shipyards. Billions of pounds of investment, an engineering project on a hitherto unknown scale, and some gallus subversive with a pot of emulsion decides to write "daft" right across it.

Inside the Queen Elizabeth, the outside world fades and you become immersed in the world of shipbuilding. It is a noisy world: the python hiss of the burning torch; the grinders which buzz like giant insects in giant jars and which throw great arcs of sparks.

The ventilation system rumbles like thunder. Blue sheet lightning glimpsed through doorways indicates a welder at work, as does the strange smell of antiseptic which seems to accompany that process.

Everyone is busy. The pride in craft is tangible. Despite the anxiety and uncertainty caused by last year's strategic defence review, which saw BAE warn David Cameron that cancelling the order for one of the aircraft carriers would lead to the closure of the Glasgow shipyards, there is a sense of determination that this job will be done well.

"It's a big thing for the boys in here," says Steven Adair, a 45-year-old welder with flames painted on his mask, "thinking that these might be the last two ships ever built in this yard."

Who knows what the future holds? Shipbuilding has always been a boom-and-bust industry and the mood of its workforce veers between optimism and fatalism. BAE has a contract to build the Type 26 global combat ship, the first of which is scheduled to enter service at the start of the next decade, although it is not yet clear whether these will be built in Glasgow or elsewhere.

The shipyard has faced closure in the past, notably in the early 1970s during the period of the UCS work-in led by Jimmy Reid and others, and in 1999 when Kvaerner announced its withdrawal from shipbuilding. The successful campaign to save the yard was led in the latter instance by Jamie Webster.

Now 60, he remains bullish about the years ahead. "My final ambition is that the day I retire there's youngsters still coming through they gates," he says. "And I'm confident I will achieve that."

Glasgow's shipyards, for Webster, are all about jobs, all about the future. Heritage is nice, yes, but these places should not be regarded as monuments. "You can look back on the past, you can learn from the past, but you cannot live in the past," he says. "As far as I'm concerned, Clyde shipbuilding is like Buzz Lightyear: to infinity and beyond."

This article was first published in Scotland On Sunday, 20 March, 2011