Non-PORC behaviour of a class of descendant p-groups

We prove that the function f(p) enumerating the number of immediate descendants of order p10 of Gp is not PORC (Polynomial On Residue Classes), where Gp is the p-group of order p9 defined by du Sautoyʼs nilpotent group encoding the elliptic curve y2=x3−x. This has important implications for Higmanʼs PORC conjecture.