From what I have read:
- Technically, the Brexit Referendum is not binding however Parliament is expected to assent to the democratic vote of the citizens of the UK.
- Only Parliament can trigger Article 50 of The Treaty of Lisbon -- and say we are OUT! In 72 hours or 7 years -- look forward to acrimonious debate in Parliament. I think, not sure, that the bill will have to be approved in the House of Commons, then be endorsed by the House of Lords and then get Queen's assent -- then it is official.
- At that point the clock starts 2 years of limbo then the EU can say we don't agree to your terms -- you have no rights other than to leave the voluntary association of the EU. In other words Fuck off Brits -- you are on your own economically -- you now need a visa to visit the countries of the EU.
The EU and UK could also enter into some trading block agreement like the US-Canada-Mexico NAFTA. There are visitor visas granted usually automatically between the US Canada and Mexico-- but there is no right of residency -- you must follow the immigration laws or stay illegally.
There may be no B2B VAT tax nor tariff or duty reciprocity. This has to be negotiated during the 2 years and if not agreed to -- so what.
NATO will probably not change much but the British might lose their strong policy prerogatives as part of the EU.