IT WAS a curiously low-key, if not flat ending to a compelling and complex story of colossal fraud, murder and legal wrangling. In the windowless wood-panelled court 25 of the High Court yesterday morning, surrounded by four unsmiling officers from the Correctional Services Department, Lorrain Osman stood stiffly to attention and listened intently as Mr Justice Mortimer told him his sentence after almost 90 minutes of deliberations. Even in his dark suit, collar and tie, Osman looked a pale imitation of the once vigorous and dynamic bank chairman he was until the Carrian collapse exploded in his face, forcing him to flee his native Malaysia for London and signalling the start of hismarathon battle against extradition to Hongkong. When the judge said ''if you have suffered great punishment, it is punishment which you deserve'', the small and balding Osman looked apprehensive and twitchy behind his spectacles. But his face broke into smiles as Mr Justice Mortimer passed a sentence of one year's imprisonment that should see Osman becoming a free man for the first time since he was arrested in London in December 1985. Yet there were no gasps of emotion after the judge finished speaking. Perhaps it was because Osman and those working with him must have known his lengthy spell on remand in London would count in his favour. Neither were there any banks of supporters in court to cheer the result. The press benches were almost full, but the reporters were busy scratching down Mr Justice Mortimer's comments. Still smiling, Osman thanked his counsel, Martin Thomas QC, through the bars of the dock. Yet, with two months of his sentence still to run, there could be no champagne celebrations or delirious scenes to mark the occasion. Then he turned on his heels and left the court with his CSD escort to return to his cell in Stanley Prison. What raw emotion there was came only from the slim and elegant Mr Thomas. Asked for his reaction to the sentence he could only gasp ''I wish I could tell you how I feel but I can't'' - his English reserve lost for the moment. The court cleared swiftly, the maintenance staff anxious to close up and get away for the weekend. The reporters hurried for the telephones to give their offices the news. The lawyers, including Director of Public Prosecutions John Wood, made their way to the disrobing rooms. After 14 years and billions of dollars, the Carrian case was concluded with a whimper and nary a bang.