Britain's Prime Minister David Cameron (4th R) walks inside the premises of the holy Sikh shrine of Golden temple in the northern Indian city of Amritsar February 20, 2013. Cameron on Wednesday became the first serving prime minister to voice regret about one of the British Empire's bloodiest episodes in India, the Jallianwala Bagh massacre, and laid a wreath at Amritsar, scene of a notorious massacre of unarmed civilians.[Photo/Agencies]