In March 2016, the British Government presented to Parliament the first part of its Report pursuant to section 7 of the European Union Referendum Act 2015, which provides a clear answer to this question in its Section 4.7:
“Every alternative to membership would involve the UK losing its vote and vetoes over how EU laws are written. And regardless of our preferences and choices, the EU will continue to be the UK’s biggest export market (at present, UK exports to the EU are worth more than two and half times UK exports to the United States – our next largest overseas market). So those EU laws will continue to be of fundamental importance to UK companies. At the moment, the UK has a significant voice in how these rules are written. Under weighted voting rules determined by population size, the UK, France and Germany have the largest voting shares when legislation is decided. We can veto decisions on such crucial issues as tax or the EU budget, when these are not in the national interest. Under every alternative we would surrender our vote and have no right to veto.”
The 54-page government report cited above is essential reading for anyone who wishes to understand the larger picture of the scope and depth of Britain's relationship with its European partners. The framework of its analysis resides in the fact that Britain will need to strike a new balance between the access it wishes to have to the European Union and its common market, the obligations it is willing to assume in order to be granted such access, and the influence it desires to have over both its European partners and the non-European countries that have struck a special relationship with the European Union as a whole. In conclusion the report states in clear terms that “[t]he UK government believes that no existing model outside the EU comes close to providing the same balance of advantages and influence that we get from the U.K.'s current status inside the EU”. In all likelihood there has never been a more factual, clearer, and more comprehensive assessment of Britain's position inside the EU and the consequences of the U.K attempting to untangle its ties of cooperation with its European partners.