First it was unfamiliar food and distance from relatives that caused judges and magistrates to agonise over jail terms handed out to foreigners and mainlanders. But yesterday's ruling in Eastern Court moves sentencing from the compassionate to the confused. Birthdays have become a mitigating factor in criminal cases. Fortunately for the dignity and gravitas of the SAR's courts, this latest plea for mercy will not become a trend. When the Nepalese defendant had a month cut from his four-month sentence on burglary offences, after he asked for a reduction because it was his birthday, a higher judge contacted by the South China Morning Post commented that it was the right length of sentence but the wrong way of arriving at it. In fact, the inmate will spend the appropriate amount of time behind bars for his crime, therefore his unique birthday present from the bench was something of an empty gesture. But the incident again points up the state of confusion in lower courts following a Court of Appeal ruling in August. In that hearing, a Swiss national, imprisoned on fraud charges, sought a cut in his sentence on the grounds that he was more severely punished by being in an alien culture. Three appeal court judges agreed that this made incarceration particularly trying, and took three months off his three-year sentence. In the weeks that followed, sentences were cut for a variety of foreigners involved in serious crimes, including drug trafficking. And when one deputy judge became over-anxious about balancing the scales of justice, he decided that since mainlanders often suffered discrimination in Hong Kong jails, they too should serve shorter sentences. An appeal judge has since clarified the court's ruling, stressing it was intended only for special cases when cultural isolation made a jail term more severe. It was not intended as a blanket ruling for all cases involving foreigners. Nor should it be. Justice must be tempered by mercy, providing it is kept in proportion. Cutting sentences for birthdays can hold the courts up to ridicule. Perhaps it is time for the Justice Department to direct the courts on sentencing policy for foreigners, and where to draw the line.