I believe if Britain leaves the EU the pound and the EUR will both bottom out from the initial shock, but then I believe both currencies will eventually recover. One of my chief concerns however would be that the pound would have a slower recovery due to uncertainty of the economy and free trade agreements with the rest of the world all of which would have to be renegotiated which could take years. Further uncertainty would likely cause the pound to depreciate due to the fact that in the event of a Brexit. It is also likely that the UK would break up into the United Kingdom of England, Wales and Northern Ireland and the Kingdom of Scotland. Still under the same monarch strangely enough, so these uncertainties would potential destroy the value of the pound. All that said I would go with the bookies.