Look around the Western world. Which country's politics seem the most shambolic? In the past, your eyes might have headed instinctively towards southern Europe. The politicians in Athens, Madrid and Rome are certainly trying hard, but if you want dysfunctionality, there are only two places to go: Washington and London.

America's government was shut for a long stretch of this year - and now President Donald Trump is stuck in a row with Congress over whether there is a national emergency on the southern border of the United States. Britain's government is meandering towards Brexit with all the discipline of a drunk on an icy road. If nothing changes, the United Kingdom will topple out of the European Union in five weeks.