Ukip, critics like to say, is little more than a pressure group. Members can be proud of that, as many pressure groups would envy how well they have secured what they want. They forced David Cameron to hold a referendum on Britain's membership of the European Union. They campaigned for Brexit, the nation voted for it, and the Prime Minister is making that happen. So what do they have left to fight for?

There is one cause that has brought Ukip's members together, and that is Brexit. Officials insist the United Kingdom Independence Party (to use its full name) is not a "single-issue" party, but its constitution lists its prime objective as follows: "It shall be the policy of the Party that the United Kingdom shall cease to be a member of the European Union". Ukip exists to campaign for Britain's "independence" with the same single-mindedness that the SNP does for Scotland. If Mrs May gives the UK its "I", what is the "P" needed for then?