 With the outbreak of war , Duncan and her sisters Diana , Daring , and Dainty , were transferred to the Mediterranean Fleet , arriving at Alexandria on 30 September . All the ships were in poor condition , and , after repair , they conducted contraband control duties . In December Duncan , along with her sister Duchess , was assigned to escort the battleship Barham back to the UK , and they departed Gibraltar on 6 December . During the morning of 10 December , Barham collided with Duchess off the Mull of Kintyre in heavy fog , sinking the destroyer with the loss of 124 lives . Duncan was assigned to the 3rd Destroyer Flotilla of the Home Fleet on 12 December . 
