... 14th regs ... REG B119 allowed Earthed concentric wiring, but in them days the ESR regs were from 1937 ...... Anyway the reg allowed 3 options one of which .... "Where the supply undertaking concerned has been specifically authorised in respect of the installation in question by the secretary of state for energy or the secretary of state for Scotland (or, outside England,wales and Scotland by the corresponding authority) to permit additional connections of the neutral conductor to earth"