The Second Periodic Review of Westminster constituencies was undertaken between 1965 and 1969 by the four Boundary Commissions for England, Scotland, Wales and Northern Ireland for the United Kingdom Parliament as provided by the House of Commons (Redistribution of Seats) Act 1949 and amended by House of Commons (Redistribution of Seats) Act 1958. The changes to the constituencies were approved in 1970 and took effect at the February 1974 United Kingdom general election.