On 29 April 1916, the 3rd Battle Squadron was rebased at Sheerness, and on 3 May it was separated from the Grand Fleet, being transferred to the Nore Command. "Britannia" remained there with the squadron until August, when she began a refit at Portsmouth Dockyard. On completion of her refit in September, "Britannia" transferred out of the 3rd Battle Squadron for service in the 2nd Detached Squadron, which had been organised in 1915 to reinforce the Italian Navy against the Austro-Hungarian Navy in the Adriatic Sea. Admiral Paolo Thaon di Revel, the Italian naval chief of staff, believed that the threat from Austro-Hungarian submarines and naval mines in the narrow waters of the Adriatic was too serious for him to use the fleet for active operations. Instead, Revel decided to implement a blockade at the relatively safer southern end of the Adriatic with the main fleet, while smaller vessels, such as the MAS boats, conducted raids on Austro-Hungarian ships and installations.