to their own ambitions. The queen could still dismiss her ministers, but power was leaching away. Anne was the last British sovereign to veto a parliamentary bill.

Britain had begun its gradual transformation, centuries in the making, into a liberal democracy with an ornamental constitutional monarchy. One consequence of getting there by evolution rather than revolution is that Britain has never had a properly codified constitution. Other nations have sat down, thought about it and inscribed the rules in famous documents with resonant phrases. We have made things up as we have gone along, with the result that many of the laws governing our politics are ambiguous and contested. We never had the equivalent of the founding fathers of the United States. Unlike postwar Japan and Germany, Britain nevercould have decided the outcome. The closeness of the result and the lack of agreement about what it meant spelled trouble from the start. It also led to the inevitable convulsions that were going to follow when a parliament largely against Brexit was tasked with implementing a result most MPs thought a mistake, a challenge without precedent. This conundrum might have been eased had Mrs May responded to her task with a non-partisan, cross-party approach, but she made things harder when she started out by seeking to please one faction of her party alone.

The conventions and culture of parliament have deepened the nightmare. The British way of doing politics is founded in the idea that power is a binary contest between two big and tribal parties. It is