In this paper we prove the generalised Andr\'e-Pink-Zannier conjecture (an
important case of the Zilber-Pink conjecture) for all Shimura varieties of
abelian type. Questions of this type were first asked by Y. Andr\'e in 1989. We
actually prove a general statement for all Shimura varieties, subject to
certain assumptions that are satisfied for Shimura varieties of abelian type
and are expected to hold in general