The M-class destroyers were repeats of the preceding L class.
Milne, being the flotilla leader, was slightly larger than her sister ships. She displaced at
standard load and at
deep load. The ships had an
overall length of , a
beam of and a deep
draught of . They were powered by
Parsons geared
steam turbines, each driving one
propeller shaft, using steam provided by two
Admiralty three-drum boilers. The turbines developed a total of and gave a maximum speed of . The ships carried a maximum of of
fuel oil that gave them a range of at . The ship's complement was 224 officers and
ratings. The ships mounted six
4.7-inch (120 mm) Mark XI guns in twin-gun mounts, two
superfiring in front of the
bridge and one aft of the
superstructure. The aft torpedo tubes were replaced by a single
QF 4-inch Mk V anti-aircraft gun. Their light anti-aircraft suite was composed of one quadruple mount for
2-pounder "pom-pom" guns, two single
Oerlikon 20 mm cannon and two quadruple and two twin mounts for
0.5 inch Vickers Mark III anti-aircraft machinegun. Later in the war, single Oerlikons replaced the .50-calibre machineguns and, still later, twin Oerlikon mounts replaced four of the singles. The M-class ships completed with only one above-water quadruple mount for
torpedoes, but the aft mount was later replaced and the 4-inch AA gun removed. The ships were equipped with two
depth charge throwers, two racks and 42 depth charges. ==Construction and career==