SOME buildings do make your jaw inadvertently fall when you first enter them. The Hermitage in St Petersburg, the Vatican in Rome, and the Houses of Parliament at Westminster have all stunned my senses. All fairly predictable of course. But another which left me momentarily speechless might seem a fanciful choice. It was the steel mill at Gartcosh on the outskirts of Lanarkshire. As a reporter I had written often about the campaign to save Gartcosh, but it was only when it closed, 30 years ago this month, that I actually saw inside.

It was one of the largest buildings I had ever been in. Three football pitches could easily have fitted within its walls. I swear there was a cloud actually below the ceiling. There were workmen inside, but they were not there to make steel. After its closure, with 700 jobs lost, those toiling inside were temporary workers removing the mill to have it reassembled in whichever foreign country had bought the kit. The sheer size of the place was awesome, and I mean that in its true sense of being breathtaking, amazing and stunning, not the trite awesome that teenagers use to describe a sandwich.

Scottish industrial power was being demolished bolt by bolt, screw by screw, and you knew Lanarkshire would never be the same again.

I have to be careful not to romanticise our industrial past. Yes, there were many noble men amongst the skilled workers who forged steel, built ships, and dug coal in Scotland. But there were many layabouts, chancers and work-dodgers as well, just as there are in all walks of life. Months before the closure I was sent by my then newspaper, the Evening Times, to accompany the steelworkers and politicians who were marching from Gartcosh to Downing Street to fight the closure. An embedded reporter, I would now be called, although the phrase was not known then. It was one of the coldest Januarys on record, and we were travelling in three caravanettes with a day's marching divided up so that each walker would do 10 to 15 miles in the snow, with another walker up ahead, so that the whole route was covered.

Tommy Brennan, shop stewards convener at Ravenscraig, who led the march, explained to me on arrival: "I said to your editor George McKechnie that whichever reporter was sent, he would have to do his share of the walking. George agreed on your behalf which was awful nice of him, but I suspect he didn't tell you." My morning would start at seven when I would be first up, trudge through the snow to find a phone-box, check of course that the handset was still attached and that the box had not been used as a toilet, and phone a story before returning to start some walking. But it wasn't really a hardship, particularly as I knew I still had a job at the end of the march, unlike the steelworkers.

Looking back, that Scotland now seems like a foreign country. For almost the whole of the eighties and nineties, there was a Tory Secretary of State, with other Tory Ministers in the Scottish Office, despite not having a majority of Scots MPs. There was no Scottish Parliament. For the most part it was a fairly benign reign. George Younger, from the family of brewers, was such a gentleman. I was with him once on a trade mission to America, and as he left the plane he spotted an elderly lady struggling with her suitcase, and he automatically carried it for her, ignoring his staff trying to hurry him along. Another minister was Lord James Douglas-Hamilton, and the story was told that when he had an official female driver, he would jump out and open her door for her while she was trying to jump out and open his door.

Then there was Malcolm Rifkind, a skilled lawyer – albeit he once got a client an increased sentence when he appealed for it to be reduced – who always knew his brief and could argue his case meticulously. Then Ian Lang, not as sharp perhaps as Rifkind, but had charm in abundance when attending the humdrum events that went with the job. Last but not least, Michael Forsyth, the most right-wing of them all, who believed that no matter how nasty the medicine was, it was for the good of the country. Think of an army field surgeon cheerfully telling you that your leg had to be sawn off. He adored Margaret Thatcher. No, he really did. I heard him introduce the Iron Lady at a constituency function in Stirling. It was like a young girl introducing One Direction on stage.

He firmly believes in free trade and would probably argue that importing steel from China rather than making our own has meant cheaper goods for Scots consumers who are being hypocritical in enjoying such products but somehow wanting steel jobs to have remained in Scotland.

But back to Lanarkshire. It was what was under your feet that made the area. Coal and iron ore. The coal drove Scotland's industries and when combined with the iron ore it produced steel. The largest steel plant was Ravenscraig, between Motherwell and Craigneuk. There are towns that are smaller than Ravenscraig was. If you drove past or saw it from a train, you would spot the two blue gas holders and three cooling towers dominating the skyline.

British Steel which ran it was owned by the Government, and Prime Minister Margaret Thatcher wanted to sell the whole thing off. But there were five steel plants in Britain, and it was rumoured that one of them had to close in order to make the remaining company more attractive for future buyers. Ravenscraig which now required iron ore and coal to be shipped in from abroad, was the likely candidate for closure, despite a workforce which had been slimmed down, had adapted to new working practices, and which consistently produced some of the best steel in the world, sought after by foreign car manufacturers.

It was an efficient plant. I was taken round Ravenscraig by the shop stewards, and the heat and noise as the steel was forged, battered your senses. But this was a modern steelworks with computers controlling the work flow, and it could argue its economic case far better than other plants. Tommy Brennan was one of only two shop stewards I have ever seen reading The Financial Times. Jimmy Reid at Govan Shipbuilders was the other. "Know your enemy," said Jimmy. For Tommy it was keeping abreast of what was happening in the industry. Every argument that Tommy and his colleagues made for retaining Ravenscraig was always backed up with compelling figures.

Then came the rumour about Gartcosh. A quarter of Ravenscraig's output was taken by train to Gartcosh where the rolling mill flattened the steel to the products buyers wanted. Removing Gartcosh would damage Ravenscraig's economic case. "Not so," argued Scottish Secretary Malcolm Rifkind defensively at Westminster, claiming that if British Steel closed Gartcosh - he was distancing the Government from any such decision, heaven forfend - then it would improve British Steel's viability and that must be good for Ravenscraig. No one believed him.

So the march to London captured the support of many back in Scotland. Even Tory MPs, who had argued that the workforce had done much to change working practices, felt that Ravenscraig should be backed, even if Gartcosh was closed.

And so it was that Ravenscraig remained open for another six years after Gartcosh was shut down - six years that took older workers nearer their pension, and six years for younger workers to make their plans for a life outside steel. Scots Tories, unable to stop the closure, ensured that as much help should be given to Lanarkshire as possible, fearing a backlash from the electorate. Iain Lawson, a former Tory parliamentary candidate who became a member of the SNP, was on the march to London. He argued at the time: "If Ravenscraig closes, the Tories will be wiped out in Scotland." In the 1992 General Election the Tories had 11 Scottish MPs. In the 1997 election they returned precisely none.

Thirty years after the Gartcosh closure I catch up with Tommy Brennan, still as sharp as ever, and a vigorous campaigner for Lanarkshire. He was one of the first to be made redundant from Ravenscraig. Funny that. We talk about the other steelworkers on the march who have since died, and I am reminded that hard industrial work is not an easy route to a long life. Politicians such as John Reid, now Lord Reid of Cardowan, who was on the march, and a journalist like me, have a better life expectancy it seems.

Tommy is dismayed that much of the Ravenscraig site is still undeveloped. There is a road through the site now, and while there is a magnificent sports centre and college, little else has been done other than removing ground contamination. There was talk of a shopping centre, but opposition from East Kilbride and Hamilton politicians, fearful of how it would affect their shops, has delayed it.

But Tommy is optimistic. "Lanarkshire Development Agency immediately identified five development sites which became enterprise zones. There has been a lot of gloom and doom talked about Lanarkshire but since the closure biotechnology companies, food distribution companies, many small enterprises have started up giving the area a much healthier economy. If any one company closed now it would not have such a devastating effect that happened with Ravenscraig."

We chat about Baroness Thatcher. "I met her twice when she was in Scotland. I remember after one of the meetings the Tory MP Anna McCurley said to me, 'Mrs Thatcher listens, but she doesn't hear'. She treated Scots like second class citizens."

He added: "I was speaking at a local school recently about steel-making, and a girl put her hand up and asked me what I thought of Mrs Thatcher. I could see the teacher stiffen. I rejected the first few thoughts that came to mind then told her, 'I think you should always try to find the good, no matter how small, in everyone. So for Mrs Thatcher I will say she brought the salmon back to the Clyde. By shutting the industries on either side of the river she cleaned it up. There you are."

But Brennan's laudable mission to talk up Lanarkshire and its recovery from the Ravenscraig closure does not convince everyone. It is argued that the well-paid jobs that the steel industry provided, leading to much needed finance flowing through the veins of the county, have not been replicated by the jobs that have been created.

Over at Gartcosh, that giant building that mesmerised me, is long gone. Part of the land is now occupied by Police Scotland's Scottish Crime Centre. Perhaps they should look into the area's history. Thirty years later I still think the butchering of a modern steelmaking industry was criminal.