The Royal Ballet season began on Saturday night with Swan Lake. This fragment of the True Cross has been in the company repertory since 1934, when the presence of the sublime Alicia Markova with Ninette de Valois’s three-year-old troupe made it possible to show the ballet in a staging that claimed direct descent from the Mariinsky Theatre creation of 40 years before. No bad lineage.

With this example, the postwar decades saw a dreadful proliferation of presentations as the Royal Ballet, by now installed at Covent Garden, made the world aware of Swan Lake’s glories. And then the Bolshoi and the Kirov brought their versions to the west, and the plague of copies spread. Swan Lake was given by every troupe that could lay hands on white tutus and hapless young women prepared to learn the double role of Odette/Odile. (Look at touring schedules of various “Russian” ensembles that scurry round the regions from northern pillar to southern post: Swan Lake as rash.)