“Heavy fog over Channel. Continent isolated.”... 

The british love their island and love to stay alone. So why the UK joint the EU but remained with the pound ? Because lived to say to the EU "if we will continue to stay in EU, what are the benefits ?" And so the EU gave many many benefits because the UK will continue to stay in EU.
Now that the EU is in crisis the british want to to Leave the sinking boat.

So british want to Leave ? Ok that all right the trade will be the same and dont kill too desperates that try to leave dunkerque for cross the Channel and land on the "continent".