Leeds 423, LUA423, AEC Regent III/Roe H31/25R at the Shadwell terminus of route 37. Entering service in December 1947 it continued to serve Leeds until October 1963.
It then became Halifax Joint Omnibus Committee 423 from July 1964 until December 1965 to cover for late delivery of new vehicles - click here for a picture.

Photo taken by John Kaye, Saturday 11 May 1957, Shadwell, Leeds