From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Notice from the Experimental Department regarding the change of the Derby telephone number.
| Identifier | ExFiles\Box 142\3\ scan0350 | |
| Date | 18th September 1937 | |
| ----- Experimental Dept. DERBY TELEPHONE NUMBER 1204 Please note that on and after October 7th 1937 the Company's telephone number at Derby will be altered from Derby 1320 to :- Derby 2424 D.{John DeLooze - Company Secretary} 18/9/37. | ||