 Before this the structure of regional broadcasting in England had remained virtually unchanged since the late 1920s, when the establishment of four regional radio transmission stations covering England had led to a regional structure on similar lines.BBC North was based in Manchester and covered the area from Cheshire and Sheffield northwards, BBC Midlands and East Anglia was based in Birmingham covering a swathe of central England from the Potteries to Norfolk, and BBC South and West was based in Bristol covering the area south and west of a line from Gloucester to Brighton.The London area, though it had regional transmission infrastructure of its own, produced only national programming and wasn't considered to be a region as it acted as the sustaining service for the other regions.