Counting the total number of church buildings and places of worship over time is not straightforward. Under the Places of Worship Registration Act 1855, legal provision was made for non-Anglican or Church in Wales places of worship to register officially with the General Register Office, which allowed marriages to be conducted on the premises. The Local Government Finance Act 1988 also provided for places of worship to be exempted from local business rates, an added incentive to register.
The official Register therefore does not include Anglican churches. The onus is on faith communities to register premises, and de-registration of disused places of worship can be slow. Further, some places of worship are informal spaces where custodians may simply choose not to register them.
The series below includes many gaps between years and so an annual count of the total should use some interpolation. Data are also available on BRIN for 1999-2009 drawing on GRO data, and the Register as of February 2015 has been made available online. Filling in the gaps would require study of the Registers at the GRO, which has been done for Muslim, Sikh and Hindu places of worship by Simon Naylor for selected years; or communication with the headquarters of individual denominations and faith communities. Since the Register only covers England and Wales, this latter approach would be necessary to make estimates of the number of Scottish places of worship.