We were reminded this morning on Broadcasting House (BBC Radio 4) of a Prom concert at the Albert Hall on 21 August 1968. The Russian cellist Mstislav Rostropovich and the USSR State Symphony Orchestra under the Russian conductor Svetlanov played the Czech composer Dvorák's Cello Concerto, amid protests and calls for the concert to be cancelled. On that day and the day before, Russian tanks had rolled into Czechoslovakia. That was some coincidence and it made musical history. A tearful Slava played the concerto with passion and anger, making it "completely clear whose side he was on."

Slava promised that he would play in Prague when the last Russian boots had gone from Czech soil. He kept his word, but he had to wait for more than 20 years...

There were no protests during the actual performance. It was released on CD eventually. It is far from the tidiest version ever of Dvorák's concerto but it's an amazing and emotional listen when you recall that context.