General Inclosure Act 1845
http://www.legislation.gov.uk/ukpga/Vict/8-9/118
if the commons were within 4 miles distance of large towns, and 15 miles of London, a proportion of the enclosed land had to be set out for recreation
10 acres above 10,000 population
8 above 5 to 10,000
5 above 2 to 5000
4 under 2000