The former transmitters of the Regional Programme continued to be used to broadcast this service, but their frequencies were changed and synchronized in order to allow them all to transmit on just two wavelengths (668 and 767 kHz) which, in the event of air raids, could be turned off in sequence to prevent their signals being used as navigational beacons by enemy aircraft.
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1927 saw 5IT closed as the opening of the high-powered Borough Hill transmitter enabled the creation of the Midland Region transmitting the BBC Regional Programme.