Excluded minors for the class of split matroids

Split matroids form a minor-closed class of matroids, and are defined by placing conditions on the system of split hyperplanes in the matroid base polytope. They can equivalently be defined in terms of structural properties involving cyclic flats. We confirm a conjecture of Joswig and Schr"{o}ter by proving an excluded-minor characterisation of the class of split matroids.