Although Somerville privately felt that such an attack would be a mistake, he carried out his orders. The French refused to comply with British conditions and so on 3 July 1940, Force H attacked French ships at Mers-el-Kébir. Somerville's forces inflicted severe damage on their erstwhile allies, most notably sinking the battleship "Bretagne" with heavy loss of life. Several other major French ships were damaged during the bombardment. The operation was judged a success, but he admitted privately to his wife that he had not been quite as aggressive in the destruction as he could have been. He was Mentioned in Despatches on 16 August 1940.