The UK can't 'leave' the EU completely. Even when we reclaim the laws and stop sending MEPs to Brussels, we cannot ignore the fact that we have a huge trading block on our doorstep, to whom nearly half our exports go. We can't ignore the fact that foreign companies have invested in the UK on the understanding that it's a gateway to the EU, nor can we ignore the fact that we have ex-pats living in the EU, who are currently receiving reciprocal healthcare.
It really isn't as easy as changing the colour of a passports or stopping those damned foreigners from coming to the UK.
Maybe somebody should ask Paul Simon to do an updated version of '50 ways to leave your lover'. There might not be 50 ways, but there is certainly more than one way. At the moment, people don't know what they voted for and the government seems muddled about it all too.