An interesting point of view:
Mr Duncan Smith, the former work and pensions secretary and leading Brexit supporter, said that the EU had "decided to leave the UK" in the late 1980s when it embarked on what he said was a one-way process of economic and political union.
Writing for the ConservativeHome website, Mr Duncan Smith suggested that, from that moment on, the UK's exit had been largely inevitable and he was confident about what lay ahead.
Source:
http://www.bbc.co.uk/news/uk-politics-39416864