The DPP39: The 39 tapes which were successfully prosecuted under Section 2 of the Obscene Publication Act. They became known as the DPP list of video nasties (or the DPP39 list). Originally a list of 72 films, the remaining 33 can be found on the Section 2 Nasties (non-prosecuted) collection.
The Act defined obscenity as that which may “tend to deprave and corrupt persons who are likely, having regard to all relevant circumstances, to read, see or hear the matter contained or embodied in it” This definition is of course open to wide interpretation.