It is not possible to give a cumulative figure for expenditure on public affairs for the Church of England, as each National Church Institution, diocese and parish is a separate charity and this information is not collected.
At a national level public affairs functions are not limited to a specific branch of the National Church Institutions. The Faith and Public Life team of the Archbishop’s Council (formerly MPA: the Mission and Public Affairs Division) handles much of the Church of England’s national engagement with Government, Parliament and policymakers but also has responsibility for work that is not public affairs. In the transition from MPA to the Faith and Public Life team under the Transforming Effectiveness process, the total number of NCI staff working in those public affairs roles has been cut.
The Archbishops’ Council Annual Report and Financial Statements for the year ended 31 December 2020 can be seen here: GS 2211 AC_annual_report_and_financial_statements_for_year_ended_31_December_2020.pdf (churchofengland.org)
The Church Commissioners for England Annual Report 2020 can be seen here: https://www.churchofengland.org/sites/default/files/2021-06/Church%20Commissioners%20Annual%20Report%202020.pdf