On 1 April 1974 the Local Government Act 1972 came into force. This abolished the existing local government structure in England and Wales (except in Greater London) and replaced it with a new entirely two-tier system. It abolished the previously existing administrative counties and county boroughs (but not the previous non-administrative 'counties') and created a new set of 46 'counties' in England, 6 of which were metropolitan and 40 of which were non-metropolitan.