Having conducted several ballets at Covent Garden during the 1970s , Boult gave his last public performance conducting Elgar 's ballet The Sanguine Fan for the London Festival Ballet at the London Coliseum on 24 June 1978 .
His last public performance was conducting Elgar 's ballet The Sanguine Fan for London Festival Ballet at the Coliseum , in London on 24 June 1978 .