EIM65815 - Tax treatment of local authority officials and employees: payments for using own car for work: general
There are no special tax arrangements for payments to employees of local authorities for using their own car for work. All mileage allowance payments are dealt with under the statutory approved mileage allowance payments (AMAPs) scheme. Full guidance is at EIM31200 onwards.
Background information
Car allowances paid by local authorities (which for this purpose include county, district and borough councils, but not parish or community councils), to employees for the use of their cars on local authority business are normally made at rates that are centrally agreed by the National Joint Council (a body that has representatives from the National Employers Organisation for Local Government Services, formerly Local Government Management Board, and from the relevant trade unions). But not all local authorities pay mileage allowances at the rates that are agreed centrally. Therefore you should always establish whether a particular local authority is paying car allowances at the National Joint Council rates, or under its own scheme.