Desmond Tutu, the South African Nobel laureate, called for an end to the "abominable" Israeli blockade of Gaza yesterday and condemned a "culture of impunity" on both sides of the conflict. Tutu was in Gaza on a three-day mission, sent by the UN Human Rights Council to investigate the deaths of 18 Palestinians from a single family, who were killed by a wave of Israeli artillery shells in Beit Hanoun in November 2006.