THREE Vietnamese families won their freedom yesterday when a High Court judge declared their detention was unlawful because Vietnam was unlikely to accept them back. Two of the applicants had been detained for more than five years in closed camps, but Mr Justice Keith stressed that although the length of their detention was 'truly shocking' he did not find it unlawful for that reason. After the case, the group's lawyer, Pam Baker, said another 125 people could hope to go free in the wake of the judgment as their cases were similar. She hoped the Government would free them without further court action. But Secretary for Security Alistair Asprey last night warned the court decision could 'send the wrong message' to a section of Hong Kong's 22,300 Vietnamese population. 'We are obviously very disappointed with the court's decision, but whether it will mean more people have to be released remains to be seen,' Mr Asprey said. Mr Justice Keith said that by law he had to consider the constraints under which the Immigration Department was operating when dealing with screening and repatriation and because of that he found the detention for such a period was reasonably necessary. Had he found otherwise, many of the Vietnamese detained in camps would be able to argue that they, too, should be released. Instead, he ordered the release of Phung Hoan, 59, his wife and three children, Tan Te Lam, 43, his wife and two children, and Ly Hue My, 28, her husband and three children, on the grounds that they had Taiwanese travel documents and Vietnam had treated them as foreign residents when they were in Vietnam. Accepting evidence that the Vietnamese vice-consul in Hong Kong had said no foreign nationals would be accepted by Vietnam, the judge found there was no reasonable prospect that the three could be removed from Hong Kong soon. Their detention therefore became unlawful. This was because the purpose for which they were detained could not be achieved and he ordered their release. A fourth applicant, Lun Tai-phong, wept as he had to return to a closed camp because he had admitted to officials his Taiwan travel documents were forged. Although Vietnam regards him as a non-national, the judge said he was sure when the authorities learn how he got his Taiwanese papers they would regard him as a Vietnamese national, and so it was likely he could be repatriated. Ms Baker said the judgment was a 'qualified victory'. She said she was not surprised the judge did not find the detention illegal because of its duration. The implications of such a finding would be huge. The judge said he had to consider manpower and financial constraints involved in the screening process, and because of this he found the length of time the families were held was reasonably necessary. He said as they had not applied for voluntary repatriation, they had to be forcibly repatriated, and he found the speed with which this could be done was out of the Hong Kong Government's hands. In the case of a fifth applicant, Ly Vinh Kien, 30, who was repatriated to China during the hearing, the judge declined to determine if his detention had been unlawful when China was refusing to accept him back. Mr Justice Keith said his case raised different questions to that of the other four. Mr Asprey said the Government had not had a chance to properly review the judgment and therefore no decision on appeal would be made until it had done so. He also called for a 'better system of understanding' from the Vietnamese Government on its willingness to accept back former residents now in Hong Kong detention centres. Government sources said the impact on voluntary repatriation could be significant.