A MAN jailed for eight years for drug offences won his appeal because the trial judge erred in his direction to the jury, but will face a retrial. Lum Wai-ming, 23, had denied possessing 78 grams of heroin for the purpose of trafficking but was convicted by a jury after a trial beforeDeputy High Court Judge Burrell in July 1992. It was not in dispute that in his summing up, the trial judge had directed the jury on the issue of presumption, which had been repealed already by the Bill of Rights. Crown counsel agreed the conviction could not stand, but said the error had been technical and the evidence strong. Jim Chandler, for Lum, said his client should not have to go through a second trial and the evidence was not overwhelming.