The First Periodic Review of Westminster constituencies was a review of constituency boundaries for the Westminster Parliament in the United Kingdom carried out by the Boundary Commissions created by the House of Commons (Redistribution of Seats) Act 1949. The Commissions reported in 1954 and their recommendations took effect for the 1955 general election. Legal action over the procedure for such reviews resulted in the passage of the House of Commons (Redistribution of Seats) Act 1958. Summary of changes Although the review was carried out only 5 years after the major overhaul of constituency boundaries enacted by the Representation of the People Act 1948 (taking effect for the 1950 general election), there were a number of significant changes, with the total number of seats increasing from 625 to 630. There were 36 new constituencies created and 31 abolished, resulting in a net increase of 5 constituencies which were all in England (506 to 511), with the number of constituencies in Wales (36), Scotland (71) and Northern Ireland (12) remaining the same. There were changes to a further 137 constituencies involving the transfer of local authorities or wards/parishes therein. There were also minor changes to 42 constituencies which involved bringing the constituency boundaries in line with local authority boundaries which had been altered. The bulk of the changes affected the large cities outside London (Birmingham, Bradford, Bristol, Edinburgh, Glasgow, Leeds, Liverpool, Manchester and Sheffield). There were only a few marginal changes in Wales and no changes in Northern Ireland. During the period 1951 to 1953, 29 Statutory Instruments, affecting 66 constituencies, had been passed under the provisions of the House of Commons (Redistribution of Seats) Act 1949 to bring boundaries in line with those of local authorities. There was a considerable delay before the Second Periodic Review was completed and approved by Parliament and this did not come into effect until the February 1974 general election. The boundaries and constituencies introduced by the First Review were therefore in use for the general elections of 1955, 1959, 1964, 1966 and 1970. List of constituencies created, abolished or altered Source: Craig, F. W. S. (1972). Boundaries of Parliamentary Constituencies 1885-1972. Chichester: Political Reference Publications. . Pages 49 to 116. BC denotes a Borough Constituency; CC denotes a County Constituency. England Wales Scotland Northern Ireland Details of major changes Abbreviations BC denotes a Borough Constituency; CC denotes a County Constituency. CB - County borough; MB