A dose of reality-nothing to do with Maggie.
The first from the Guardian, so it must be correct!

https://www.theguardian.com/business/2016/mar/29/crisis-british-steel-tata-40-years-making

http://www.manchestereveningnews.co.uk/news/nostalgia/way-were-cotton-king-manchester-6085736

http://www.newstatesman.com/culture/culture/2013/01/meeting-our-makers-britain%E2%80%99s-long-industrial-decline

Very easy to generate the links for any industry and check the statistics yourselves. There is no point in singling out Thatcher for blame, she became premier with an inherited situation. Guilt can be shared in all directions. The major problem with government is that it only recognised the severity of the problem with hindsight. Consequently solutions offered were too little, too late. Sticking plasters do nothing to aid a corpse.
DEREGULATION was the mantra of Reaganomics and was adopted indiscriminately.
de regulation
Some would argue it was the best thing since sliced bread, others that it created an uncontrollable economic nemesis. All depends where you are coming from.
To blame the underlying structural changes of British Industry on a sinle politician is patently absurd and naive in the extreme. Socialists need to learn basic economics and history.