From the Historic England entry:
“HISTORICAL NOTE: this store and offices was the flagship of an organisation founded in 1914 which became the largest men’s clothing organisation in the world, offering quality clothes at the cheapest possible prices. Burton was also a pioneer in the field of industrial welfare in an exploitative industry.
c1929-30. By Harry Wilson. For Montague Burton. Stone faced steel frame. EXTERIOR: 7 storeys on a corner site. 7 bays to main Oxford Street facade, recessed canted angles 1 bay each,

left hand return to Tottenham Court Road 3 bays, right hand return 2 bays. Ground floor shop altered late C20. Mezzanine 1st floor with margin glazed, tripartite metal framed windows in plain rectangular recesses.
Main facade with Greek detailing to 6 Corinthian pilasters rising from 1st to 3rd floor to support an entablature with projecting cornice surmounted by antefixae. Within this frame, metal framed tripartite windows with spandrel panels to 2nd and 3rd floors. Outer bays with narrow, vertically set windows to 1st, 2nd and 3rd floors. Attic storey has short, horizontally set windows above which a stepped parapet with shaped, architraved, horizontally set window surmounted by a winged cartouche. Tottenham Court Road facade similar. Recessed angles with distyle-in-antis fluted columns, otherwise similar with stepped back parapets. Right hand return, plain recessed openings on 4 floors, tripartite to left bay, paired to recessed left bay.
INTERIOR: not inspected.”