Firstly we are having a referendum because DC had to appease the right wing of his party coming up to the last general election. This referendum is more about the Tory Party than it is about Europe. The first bit for DC was easy, but now having held his party together with that promise, well he has to deliver - not so easy - and if he fails to win, well he will have won an election only to have taken to country out of the EU and destroyed his political career. Not to mention left the UK close to splitting itself.
Secondly, there is all the workplace legislation that is good for us all. One reason many Tories hate the EU is it gives us workers rights. The human rights act too, it would be a disaster if leaving the EU opened the door to scrapping it.
And of course the EU is the single biggest open market in the world, being a member gives us full access, and full influence. If we leave we will need to sign up to a trade agreement, ie pay money for the same access but have no clout or say in return, and we will have no guarantees whatsoever. Economically your immediate trade partners are always your most important and reliable.
CE standards will still be set by the EU, if we leave we will have no say but will have to abide by them, as we will in so many other ways but will have no say.
If there is any threat to our access to the EU market many big companies will leave. Big companies like Nissan and Honda for example came here because we were the perfect EU base, they'll already have their exit contingency plans drawn up.
Scotland - Vote no, take us out - and it appears that Scotland will vote to stay by a considerable majority - there will be another Independence Referendum and the UK will be no more, outside of the EU as the independent Scotland signs up to continue it's membership.
Yup DC has created one hell of a nightmare for himself.
I'll be voting to stay in.