| Level | Item |
| Reference Number (click to see whole series/group) | E5/20 |
| Extent | 1 file |
| Title | PREMISES: HEAD OFFICE, LONDON, AND GENERAL - PROTECTION OF PREMISES BY RADIO |
| Date | 16 Dec 1955 - 31 Dec 1964 |
| Description | Equipment. Radio Control Room and Radio Operator. |
| Original Reference | P563v2 (v1 apparently destroyed) and a few papers from C378 |