The Southampton class were developed in response to Japanese cruisers being built that were reported to have a displacement of 8,500 tons and armed with fifteen 6.1" guns. Despite most experts feeling this was impossible the British Admiralty asked for designs for something similar. Four designs were put forth and one that had four triple 6" turrets, a speed of 32 knots and 3 aircraft was chosen.
The Southampton and Newcastle were a part of the 1933 Program.
The Sheffield, Glasgow, and Birmingham were part of the the 1934 Program.
The Gloucester, Liverpool, and Manchester were part of the 1935 Program. These had additional horizontal armor.
There was a single catapult for the three aircraft carried. There was a hanger that could hold two aircraft.
The 6" guns could elevate to 45°. The charges were hand passed to the guns.