As of 19 June 2006, the Home Office operates 41 websites. This does not include approximately 20 non-departmental public body (NDPB) sites, which are affiliated with, but independent of the Home Office. The core Home Office website also has a number of sub-domains, such as police.homeoffice.gov.uk, which act as portal sites for practitioners around policy issues. The Home Office does not keep a central record of costs for all departmental websites, and would not be able to collect this information without incurring disproportionate cost.