They were rebuilt from LMS Patriot Class locomotives (which were the fourth type of LMS 2A boilered 4-6-0 locomotives) over the period 1946–1949.

[1] Between 1946 and 1949 eighteen LMS Patriot Class engines were rebuilt with Stanier 2A boiler, cab and tender, though these were largely paper rebuilds, based on the LMS Rebuilt Royal Scot Class.

Seven (Nos 5514/21/6/9-31/40) had been rebuilt by the start of 1948 when British Railways inherited them.

The two original members of the class, and the first ten of the nominal rebuilds, were not rebuilt due to their non-standard parts.

[2] The rebuilt Patriots were withdrawn between 1961 and 1965[3] in accordance with the BR Modernisation Plan and none were preserved.