[holding answer 25 February 2010]: Annual estimates of net supply have been made from annual changes in housing stock since the late 1960’s. Prior to that estimates were available every 10 years from the population census, back to 1801. In 2000-01 a new data return was introduced to improve estimates of net supply.
Figures on net supply of housing and an explanation of data sources are included in Communities and Local Government’s statistical series “Net supply of housing, England”. Statistical releases in this series can be found on the Communities and Local Government website at the following link. The latest release was published on 25 February 2010.
http://www.communities.gov.uk/housing/housingresearch/housingstatistics/housingstatisticsby/stockincludingvacants/nethousingsupply/