It’s the dilemma facing millions of moderate Labour voters: can they in good conscience support their party this time around without endorsing Jeremy Corbyn? This is no mere academic puzzler. Many are horrified at the transformation of their party from Europe’s most successful social democratic movement into a glorified protest group, and one with more than its fair share of cranks.

Labour’s failure to come to grips with the anti-Semitism now commonplace in its ranks is politically ill-considered, not to say reprehensible. But for those drawn to Labour for its history of fighting racism and discrimination, it is another indication that this is no longer their party.