There's an old saying: "A lie told often enough becomes the truth". It's one 'comedian' and former Socialist Workers Party member Mark Steel should know well, it comes from Lenin after all, and he certainly seems to be taking it to heart.

Steel's recent piece for The Independent is titled 'You can't just shut us up now that Margaret Thatcher's dead'. Oh, that we could! Steel has, after all, built a career out of the sort of dated, unamusing jokes about Thatcher that guarantee you steady work at the BBC. Personally I don't know why the Indy hasn't given Tim Vine column inches to opine on deindustrialisation, at least he’s funny.

And it wasn't long before Steel broke out the Big Lie: "in 1980 Margaret Thatcher’s government shut down most of the steel industry, as part of her plan to break the unions". You hear this argument a lot, as though repeating it will make it true. But a look at the facts shows that it isn’t.

In 1955 the British steel industry was working at 98 percent of capacity. But, over the following years, this declined as a result of its failure to adopt new methods (such as the basic oxygen steel-making process and continuous casting) and increased steel production in other countries. By 1966 just 79 percent of capacity was being utilised.

The following year a large chunk of the British steel industry was renationalised (it had been nationalised for a few years in the early 1950s). In 1970 the new British Steel had a record output of 23.8 million tonnes (4.7 percent of the world total, down from 25 percent in 1929).

But the industry was now being run for political rather than economic ends and massive over-manning and consequent low productivity became endemic. By 1977 output had actually fallen to 20 million tonnes (3 percent of the world total). By 1978 British Steel was operating at just two-thirds capacity. And by 1979, British steel workers were a third less productive than their French competitors and 40 percent less productive than West German steel workers.

In the fiscal year 1978-1979 British Steel lost £309 million. This rose to £545 million the following year, one in which workers struck for six weeks for a 20 percent pay rise. They got it, but my dad, who worked in a steel works in Sheffield at the time, said that by the time they went back to work their foreign customers had gone elsewhere.

In 1980-1981, British Steel lost a staggering £1 billion on turnover of £3 billion, earning itself a place in the Guinness Book of Records. By contrast the output of Britain's small private sector steel industry doubled between 1967 and 1979, from 3 million tonnes to 6 million tonnes.

Between 1967 and 1974 employment in the British steel industry fell from 250,000 to 197,000. And by 1990 it had fallen again by 74 percent to 51,000. But other developed countries also saw drastic declines in employment in their steel industries in the same period. In France, for example, employment fell by 70 percent, while in the United States it fell by 60 percent. Even Germany lost 46 percent of its steel workforce.

What happened to towns like Sheffield or Corby was not part of some Thatcherite vendetta and instead was part of a general trend across the industrialised world. It happened in the Rhur Valley and Ohio, was Maggie Thatcher responsible for that too?

And given that the British steel industry’s problem was chronic over-manning, which caused low productivity, it is, sadly, fantasy to suggest that there was some painless cure that didn’t involve a reduction in employment.

Indeed, in the following years British Steel recovered. Whereas in 1976-1977 it had taken a British steelworker 15 man hours to produce a tonne of liquid steel, by 1986-1987 it took just 6.2 man hours and that year British Steel turned a profit of £177 million on turnover of £3.5 billion. When the company was privatised the following year it had made a profit of £410 million on turnover of £4.1 billion. By 1997 British Steel was the most profitable integrated steel company on the planet.

So British Steel was not shut down by Thatcher “as part of her plan to break the unions”; it was privatised because it was an economic basket case. Like the coal industry it was dying by the time she got elected.

This is the truth behind the Big Lie. That industries like steel and coal were ravaged is true. That it was painful for those involved is also true. But that it happened simply because Margaret Thatcher wanted to “break the unions” is false.

But maybe I’m missing the point with all this. That was certainly the opinion of some people I spoke with recently when I explained the advanced state of decrepitude the coal industry was in when Thatcher took over. “Oooooooh facts and figures. Go on then, how many miles have you walked in pit boots?” said one. Another said I was “someone who tries to hide behind certain facts and figures without giving the whole truth of the situation”.

It’s a curious argument to suggest one can get a better view of “the whole truth of the situation” by walking around in “pit boots” rather than looking at the entire industry and the economy as a whole. But then these people were from an area heavily affected by all this. For some the strength of that experience, reinforced by repetition over the years, has compromised their ability to examine the issue rationally. This is not to ignore what they say; experience is valid and should be recorded as such, but it should not be mistaken for analysis.

Perhaps Mark Steel isn’t being deliberately dishonest and this applies to him too. I’ve no idea and little inclination to find out. But you can’t blame a guy who trades on hating Margaret Thatcher for giving his routine one last airing. After all, when Maggie Thatcher died so did half of Mark Steel’s act.

I am indebted to the article ‘The British Iron and Steel Industry Since 1945’ by Alasdair M. Blair

John Phelan is a Contributing Editor for The Commentator and a Fellow at the Cobden Centre. He has also written for City AM and the Wall Street Journal Europe. He blogs at Manchester Liberal and Tweets @TheBoyPhelan