In those days, the telephone system in the country was provided by the GPO, the General Post Office. The Defence Control System of Fighter Command relied entirely on land lines for its communications. Thousands of miles of new landlines were laid, linking the radar installations on the coast to Fighter Command Headquarters at Bentley Priory, and from this control centre to Group Headquarters, to the Sector Stations and to the Squadrons on the airfields. As the Luftwaffe raids intensified on airfields, it was these vital communications which were, just as much, the target as the aircraft themselves.

Teams of GPO engineers were kept frantically busy by bombs destroying telephone lines and telephone exchanges. It was a matter of the highest priority to restore damaged facilities to working order. GPO engineers were immediately on the scene following a raid and were straight away at work, putting the system together again. Nobody who saw the work they did at the time ever complained about the GPO in later life.