The protracted debate over the future of UK economic policy and its relationship with EU monetary union has once again surfaced in the context of automotive industry investment. Sterling appreciation against the euro is causing difficulties for companies and plants in the UK that rely on sizeable exports to continental Europe. This time it is Nissan that is making dark noises about future investment in the UK. And this from a company that boasts, in its UK operation, the most productive plant in Europe. What is the background and what are the most likely outcomes?