International companies from outside the EU – from, say, the US, Japan and, indeed, Australia – base themselves in the UK in no small part so they can access the wider European market. The single market is especially beneficial for your vibrant and world-beating financial services industry, which benefits from having all of Europe as its home market instead of just Britain. I can see no good reason why the UK would want to give up such a beneficial economic relationship with its nearest and largest trading partners – nor am I clear what you would replace it with.