Oxides with tetragonal tungsten bronze (TTB) structures are an important class of ferroelectrics with properties relevant for several technological applications. The interactions between the chemical disorder and local polar atomic displacements that control the ferroelectric response of TTBs remains uncertain. The proposed experiments aim to determine the local structure in a representative TTB using neutron total scattering and other data, with a goal of getting a better insight into the structure-property relations in these materials.