“Henry VIII is the only king whose shape we remember,” David Starkey tells us in the first of a new series of “polemical essays” on British art. To demonstrate, he reduces the king’s form to its bare Cubist geometry. He sketches a trapezoid for the chest – an impressive 54 inches in life, as attested by his made-to-measure suit of armour; two “chicken-wing” triangles for the puffed sleeves; two simple parallel lines for the wide-apart legs. Oh, and a small, inverted triangle for the codpiece. This last addition, as originally drawn-in for comedic value by the Tudor historian G R Elton, and fondly recalled, never failed to raise a titter amongst the callow students of Dr Starkey’s Cambridge undergraduate days.