It was the UK who refused to control the dumping of cheap Chinese steel, not the EU
From Full Fact:
Start
European Commission plans to raise duties haven’t been supported by Britain
In 2013, the European Commission submitted plans intended to discourage what it called certain “unfair trading practices”. These would allow the EU to impose higher import duties in cases where it believes a government is subsidising exports in a way that undermines a raw materials industry in Europe, such as steel.
Britain has been accused by both trade bodies and other European officials of blocking these reforms.
"European Council"
This is the place where EU heads of state or government meet at least four times each year, but more often if necessary. It plays a major role in setting the EU’s overall agenda and is the EU’s ultimate political authority. It was the European Council that decided to accept David Cameron’s renegotiation package.
We don’t know the precise position taken by British ministers in European Council discussions—these usually take place in private. We do know that the UK signed up to a memo sent to the committee tasked with overseeing the reforms, calling for the status quo to be maintained.
This would have kept in place limits on the tariffs the EU can impose through the lesser duty rule’.
Business Secretary Sajid Javid has also said the government doesn’t wish to see “disproportionate” duties introduced, arguing that this could have a negative impact on companies which use, rather than manufacture, steel in the UK.
British objections to the reform of anti-dumping measures are nothing new. The EU dropped a similar attempt to change European law on the matter in 2008, with then-EU Trade Commissioner Peter Mandelson stating that he didn’t want “to bring forward proposals prematurely that would exacerbate differences among member states”.
End
fullfact.org/europe/is-uk-calling-for-lower-eu-duties-chinese-steel/
And the EU is moving on it now that the UK is more or less out of the picture
European Commission Imposes Anti-Dumping Duties On Chinese Steel Products
May 17, 2017
money.cnn.com/2017/05/12/news/economy/china-steel-europe-dumping/index.html
Incidentally, when the Single Market and Free Movement of workers was set up, guess who didn't want a brake on admitting EU workers?
Why, Maggie Thatcher
So much Fake News has been fed to UK citizens over the years and they swallowed it hook, line and sinker...