National Counter Terrorism Security Office
A security services body, also called NaCTSO
This authority is not subject to FOI law, so is not legally obliged to respond (details).
The National Counter Terrorism Security Office (NaCTSO) is a police unit co-located within the Centre for Protection of National Infrastructure (CPNI). We have been advised that the The National Police Chiefs' Council (NPCC) deal with FOI requests to NaCTSO so requests are sent to them. It may be worth making explicitly clear that any request refers to NaCTSO.