The line arrives like a dropped pint glass in a carpeted committee room: sharp, sudden, and impossible to ignore. Moral issues, it suggests, do not become complicated because the world is subtle, but because the people charged with judging it have misplaced the measuring stick. The observation belongs to G.K. Chesterton, though it now wanders the modern age like an unattended suitcase, growing heavier with every mile.

Britain has developed a curious surplus of weathercocks. They occupy television studios, ministerial offices, think tanks, conference platforms and occasionally entire front benches. They swivel magnificently. Every breeze receives immediate acknowledgement. Every passing gust of public opinion produces a fresh adjustment. Every opinion poll sends another metallic creak echoing across Westminster like a church steeple caught in a North Sea gale. The country has become crowded with men and women who can detect a shift in public sentiment from three counties away, yet somehow remain incapable of explaining where the nation ought to be heading.