NOW that the United Nations High Commissioner for Refugees (UNHCR) has so unequivocally washed its hands of the problem of the Vietnamese boat people, it is time to begin considering seriously what will happen to the thousands likely to be still stranded in Hong Kong's detention centres after the 1997 handover. Until now, this has not been necessary because of the Government's repeated assurances that it would clear the camps - if not by the end of this year, as originally promised, then at least before 1997 - were widely believed. But now, few officials still bother to pretend that this deadline can be met, and the UNHCR's new Asia-Oceania Director, Alexander Casella, has made it clear that the agency's priorities must, in future, lie elsewhere. At a time when millions of Rwandan refugees remain stranded without shelter in Zaire, it is difficult to argue with that. This means that, whatever the eventual solution to the boat people problem, it will lie in Hong Kong's hands - and that increasingly means in China's, too. Beijing can justly argue that, as it always opposed the British Government's adoption of the Port of First Asylum policy under which the Vietnamese were admitted, it has no obligation to keep them in the territory after Hong Kong reverts to Chinese sovereignty. Even were Beijing otherwise inclined, the post-1997 Special Administrative Region government is sure to strongly press for the forcible deportation of any remaining boat people, if only to boost its popularity with the Hong Kong public. Although the price of housing the Vietnamese has declined, along with their numbers, the shopping list of improved security measures outlined in yesterday's final report on the High Island Detention Centre break-out will inevitably boost costs once more. Equally inevitably, this will further fuel local resentment at having to pay for a problem not of the territory's making. Yet China would be wise to think twice about forcibly repatriating boat people to the border with Vietnam or interning them in mainland re-education camps - the options apparently now under consideration. Beijing should remember that, however unfair this is, the world tends to judge Hong Kong on how it treats the boat people, with one riot in a detention centre generating more damaging TV footage than any number of human rights violations. After 1997, this will be doubly true. Brutal scenes accompanying a mass deportation would give a terrible image of China resuming sovereignty. Instead, Beijing should recognise that, while it is right to protest at being left with the boat people problem, there will be no quick-fix solution after the handover - and it would be wrong to try to find one.