Prospective
Note: The following abbreviations are used in this Table:—
| 1949 = | The House of Commons (Redustribution of Seats) Act 1949 (12, 13 & 14 Geo. 6 c. 66) |
| 1958 = | The House of Commons (Redistribution of Seats) Act 1958 (6 & 7 Eliz. 2. c. 26) |
| 1963 = | The London Government Act 1963 (c. 33) |
| 1972 = | The Local Government Act 1972 (c. 70) |
| 1973 = | The Local Government (Scotland) Act 1973 (c. 65) |
| 1979 = | The House of Commons (Redistribution of Seats) Act 1979 (c. 15) |
| SL(R) 1986 = | The Statute Law Repeals Act 1986 (c. 12) |
| S.I. 1951/753 = | The Transfer of Function (Minister of Health and Minister of Local Government and Planning) (No. 2) Order 1951 (S.I. 1951/753) |
| S.I. 1968/1656 = | The Minister for the Civil Service Order 1968 (S.I. 1968/1656) |
| S.I. 1970/1681 = | The Secretary of State for the Environment Order 1970 (S.I. 1970/1681) |
| S.I. 1973/2095 = | The Local Government reorganisation (Consequential Provisions) (Northern Ireland) Order 1973 (S.I. 1973/2095) |
| S.I. 1981/1670 = | The Transfer of Functions (Minister for the Civil Service and Treasury) Order 1981 (S.I. 1981/1670) |