sentences:  Boundary reviews were considered county by county unless, in the interests of producing more equal constituencies, two or more review areas (administrative counties and county boroughs between the redistributions of 1918 and 1974) were combined for a particular redistribution.In 1918 Rutland, the smallest of the historic counties was joined with part of another county, but it was rare for an English constituency to cross county or county borough boundaries before the redistribution of 1983, which was based on the altered local government arrangements introduced in 1974.Since then the Boundary Commission for England has more often combined review areas to create cross border constituencies.