In this remarkably concise speech, author Frederick Forsyth makes it clear that remaining in the EU, i.e. after the referendum, would not mean that the status quo would continue. Serious concessions will have to be made. As things stand, the United Kingdom is not a fully committed member; it's not a part of the Eurozone and it's not part of Schengen, which are the two pillars of the European Union. If the UK votes to remain in the EU, it will be understood as a vote to "be at the heart of Europe", and thus the United Kingdom will inevitably have to sign up to both.
However, Forsyth brings up a third pillar (and thus future concession) that the European Union is currently working towards, and that is corpus juris, i.e. the unification of the criminal codes in all jurisprudences right across the continent. Corpus juris is based on the Napoleonic Code and is thus radically different from Anglosphere, common law.
The above is all further proof that the European Union is a revived form of the Soviet Union; various peoples and languages trapped within one currency, one border and one legal code and governed by a sclerotic, incompetent and bloated bureaucracy that regulates everything from speech and thought to the size and shape of a banana and is answerable to no one.