Leave. Leaving doesn't mean we can't maintain good relationships and set up trade deals with the remaining European countries, I read that 'a brexit will set the UK back £11 billion!' however we are currently spending around £14 billion on our EU membership or something like that (can't say those figures are right, that's just what some research has thrown up) so we would actually be saving money (the difference is around 0.2% of our GDP per annum), when it comes to things like security we will still work closely with countries we have historical and cultural ties to like France to combat threats like ISIS, in a similar way we have a working relationship between Britain and American security services. With regards to trade again, leaving the EU means the UK can pursue international trade deals outside the dwindling EU with stronger powers like China and India which EU law currently prevents us from doing and personally this whole 'special status' thing is ridiculous, I think the countries of the EU should all be treated equally or get out.