Most large public housing estates comprise a mix of tenures: social rent, resident freeholders or leaseholders, and private tenants. Inner London and the inner areas of major British cities are typically made up of large public housing estates, some constructed in the inter-War years with the majority constructed after 1945. The law and practice of compulsory acquisition in England and Wales in highly complex, having been constructed over a period of over 170 years both through legislation and case law. Powers of compulsory acquisition have been used extensively in the United Kingdom to facilitate large scale urban change, for instance in establishing New Towns, large scale town centre improvements, and major urban regeneration schemes on brownfield or previously developed land. Designated New Towns were governed by a development corporation with wide powers to acquire land, either by agreement or compulsory purchase.