  In this paper we characterize primitive branched coverings with minimal
defect over the projective plane with respect to the properties decomposable
and indecomposable. This minimality is achieved when the covering surface is
also the projective plane, which corresponds to the last case to be solved. As
a consequence, we have extended the family of realisations of branched
coverings on the projective plane and established a type of generalisation of
results on primitive permutation groups.
