Cuba has been marking the 52nd anniversary of the rebel assault that launched Fidel Castro’s revolution, but the country has done so under a cloud of growing social discontent.Castro himself was at the centre of the celebrations. However this year he addressed supporters not in a traditional outdoor mass rally but in the more controlled surroundings of Havana’s Karl Marx Theatre. The Cuban president was speaking amid a fresh crackdown by his communist government. It seized 33 dissidents on Friday. Several are still said to be detained. On the streets, billboards proclaim that: “We are doing well”, but critics say most Cubans have little cause for cheer, faced with economic hardship, dilapidated housing, low wages and shortages of food. Record heat and lengthy power cuts have only heightened tensions, sparking scattered protests, according to human rights sources.