Perovskite titanates with nominal stoichiometry ABO3+Δ are frequently reported in SOFC literature as having O3 stoichiometry. Such phases often exhibit quite interesting properties, but are not stoichiometric and the structural characterisation is usually not rigorous. Here we demonstrate how oxygen excess can be incorporated in a titanate perovskite-based lattice as crystallographic oxygen shears giving rise to the homologous series La4Srn−4TinO3n+2. The layered structure is lost for the n=12 member (La4Sr8Ti12O38−Δ), although the oxygen excess is accommodated within the perovskite framework in randomly distributed short-range linear defects. This compound was studied as potential fuel electrode due to its high total conductivity and stability in the most reducing conditions.