You could call him the final witness. A man who could see what was happening to the world he knew. Factories. Tenements. Warehouses. Foundries. Laundries. Carpet-makers. Bakers. Trams. Horses. Carts. Locomotives. Chimneys. Pistons. Girders. Steel. Steam. Smoke. John R Hume saw it all in the streets when he was growing up after the Second World War, but by the 1960s, 70s and 80s, he could also see that it was starting to disappear. So he took out his camera and started taking pictures.

The result was a collection of 25,000 photographs that provides a remarkable record of industrial Scotland, which rose rapidly but fell rapidly too. Hume was there when the tenements were pulled down and the canals were filled in and the tram-rails were pulled up. He recorded the destruction of some remarkable and beautiful buildings, such as the great Venetian-style UCBS bakery on the Clyde, but he could also see the beauty in architecture others might dismiss: mills, yards, refineries. And he saw the people who worked in them and he felt for them. As the buildings came down, so too did their jobs and livelihoods and communities.

So great was Hume’s passion – sparked at first by the world he could see from his parents’ flat in Clarkston – that he became one of the pioneers of a new discipline: industrial archaeology, the systematic study and recording of what remains of our industrial past. After many years in academia, he also became a principal inspector of Historic Scotland and as such was responsible for recommending which buildings should, and which should not, be listed. Now in his 80s, it has given him a remarkable relationship with the past. He can see buildings that are no longer there. The past, for him, is still present.

And it started early. One of Hume’s first memories is being taken from his cot when he was two during the Clydebank Blitz and seeing the bombed-out houses and churches in the days that followed – one of the reasons things started to change, he notes wryly, is that the Germans started bombing them. He also remembers looking out from his parents’ top-floor flat in Clarkston Road and seeing the horse-drawn vehicles and trams. And he remembers the nearby G & J Weir foundry which made pumps and also did its bit for the war effort.

“When I was at primary school,” he says, “I used to think that all the things I could see were worth preserving. Maybe somewhere in heaven there’s a place where all these places will be remembered.”

Hume, although a lover of the past, is not a purist, nor someone who thinks history must be preserved at all costs. Some of the pictures in a new book that feature his photographs, A Life of Industry, demonstrate how that great ribbon of concrete, the M8, slashed its way through Glasgow, but Hume recognises the change that swept away many of the buildings in Scotland’s cities was inevitable.

“A lot of the industries I photographed were past their time,” he says, “but the process of change was not very well considered and the idea that you could sweep away great physical chunks of the city and replace them with something better was quite wrong.

“Even at that time, I was aware that what was happening in the 1960s was the destruction of old, established communities where everybody knew each other and worked together. They went to the same shops and pubs, and it was all tied in and there was a lovely warmth about it. The political context which developed after the war was that old was bad.”

This emotional and personal link to bricks and slate and steel is at the heart of Hume’s philosophy and played a part in the principles that guided him when he decided whether a building should be listed. “There were four principles,” he says. “One was: is this a building of quality, one that has a basic integrity of design and purpose and does a job? The next was: does the building contribute something positive to its environment, do people feel better for seeing it?

“And the next was: does it relate well to the other buildings it’s associated; one of the great weaknesses of modern construction is that there are far too many far too big buildings which stick out like a sour thumb. And the fourth thing would be: is it a building people love?”

You can see these principles at work in Hume’s life and his photographs. He remembers the Candleriggs fruitmarket, just down the road from Strathclyde University where he was a lecturer, and he remembers how much the men and boys loved working there.

And he’s thinking of the tenements he grew up in and the tenement he still lives in now. Tenements are a triumph of design, he says: social and yet private at the same time and for him it was a disgrace that so many were reduced to rubble and replaced with high-rises buildings. Humans weren’t made to live like that, he says.

The legacy of development or destruction – whichever word you prefer – and the piles of rubble mean that Hume’s verdict on whether Glasgow has been successful in preserving its heritage is mixed.

For him, it is the finest Victorian city in the world but many people just don’t realise it. “People don’t value the quality of the architecture that still survives in the city centre,” he says. Decades of flawed and thoughtless development have also done their bit. Glasgow is a scarred beauty, he says, but scarred beauty is often the best.

As for the future of Glasgow and Scotland’s other towns and cities, Hume is reasonably positive.

“I think the town centres are reasonably safe – some offices will close, in fact some of them ought to close because they’re pretty dull, not just dull, they’re harmful and energy sapping. But some can be re-purposed for cultural purposes of one kind or another.

“I can see widespread demolition happening within the next few years.”

He also hopes that, if we could time-travel forward 50 years, we would find a lot of Glasgow the same as it is now. “You might see quite a lot of Glasgow that you know and love,” he says. “There will be replacements – buildings will be damaged by fire – it is one of the great destructive forces in Glasgow, largely deliberate. But what I would hope for is that future generations will realise what a wonderful city it is and will either keep the buildings that are keep-able or build worthy replacements – buildings that are not too tall or too wide and fit into the city’s plan and they have a special something that is of their generation.

“It’s worth fighting for, that one. Buildings are the most fundamentally important thing in the world.”

A Life of Industry: The Photography of John R Hume by Daniel Gray is published by Historic Environment Scotland at £20