Whenever a substantial benefit was likely to be achieved for one of the purposes listed in s 7(1) of the Criminal Justice Act 1987 any question of the admissibility of evidence or of law which had been raised by either party to criminal proceedings could be determined at a preliminary hearing pursuant to s 7(1), rather than at the trial proper after a jury had been sworn in, regardless of whether the question concerned had been raised in order to further one of the purposes listed in s 7(1).