  We prove that every projective special K\"ahler manifold with \emph{regular
boundary behaviour} is complete and defines a family of complete quaternionic
K\"ahler manifolds depending on a parameter $c\ge 0$. We also show that,
irrespective of its boundary behaviour, every complete projective special
K\"ahler manifold with \emph{cubic prepotential} gives rise to such a family.
Examples include non-trivial deformations of non-compact symmetric quaternionic
K\"ahler manifolds.
