See Daniel H Wright’s piece on Leslie Green at https://thebeautyoftransport.com/2013/10/09/the-green-agenda-leslie-green-underground-stations-london-uk/
See also M@londonist.com: https://londonist.com/london/transport/leslie-green-tube-stations-map
From: Historic England entry for Russell Square Underground Station:
“One of the most impressive surviving Leslie Green underground stations, including a largely intact faience facade retaining original tiled lettering.
Reasons for Designation
Russell Square Underground Station is designated at Grade II for the following principal reasons:
* Architectural interest: a good example of a station designed by Leslie Green to serve the GNP & BR, later the Piccadilly Line, retaining original tiled lettering * Interior: while altered, features of interest survive at lower levels including tiling and directional signage * Historic interest: the Yerkes group of stations designed by Leslie Green illustrate a remarkable phase in the development of the capital’s transport system, with the pioneering use of a strong and consistent corporate image; the characteristic ox-blood faience façades are instantly recognisable and count among the most iconic of London building types * Group value: with listed buildings in Bernard Street, including the Hotel Russell (Grade II*)”