It is not the stuff of Khrushchev unmasking Stalin, nor the fall of China's Gang of Four, but a three-hour film being shown to thousands of the Cuban Communist party's 1m members this summer has emerged as a rare admission that all is not well at the pinnacle of power in Havana.

The video footage is drawn largely from a March meeting of the Communist party politburo and features Raúl Castro, the president, sacking most of the cabinet he inherited from his ailing brother, Fidel, including prominent political figures such as Carlos Lage, vice-president and Felipe Perez Roque, foreign minister.