The American sage H.L. Mencken once observed that “there is always a well-known solution to every human problem – neat, plausible, and wrong.” He could almost have been commenting on the decision to hold a UK referendum on membership of the European Union and the subsequent campaign.

In the form that his remark is commonly misquoted, “for every complex problem there is an answer that is clear, simple, and wrong”, he would have been exactly correct. The truth is that human beings do not like complex problems – in this case, for instance, the weighing in the balance of two unquantifiable risks, where the things “we don’t know, we don’t know” overshadow everything else. People inevitably prefer to reduce them to binary choices, remain or leave, in or out; and to identify clear, simple solutions, such as that most of the problems the UK faces can be resolved if it were not for uncontrolled immigration, courtesy of the EU’s insistence on the free movement of labour.

David Cameron chose to hold a referendum as the neat and plausible solution to his problems with the Eurosceptic wing of the Conservative Party. There was at the time a danger of Tory voters flirting with the United Kingdom Independence Party (Ukip) and hence threatening his chance of winning the next general election. He did win, the referendum is imminent, and  yet it is only too plain how wrong the Prime Minister was to think it would restore peace to the Tory Party. He appears not to have anticipated for a moment a far graver outcome – that the result could tip Britain out of the European Union altogether. If anyone needed to heed H.L. Mencken’s warning, it was him.