When an official from the Antiquities and Monuments Office suggested in January that one of Hong Kong's temporary housing units should be preserved as a museum piece, he, like everyone else, was taking the Government's demolition pledge at face value. Temporary housing would be virtually gone by the end of 1997, the public was assured last year. But that was a promise Hong Kong had heard before. Housing officials have been forecasting the demise of the units for decades; and no doubt everyone who ever said they would disappear genuinely believed this would happen. The reality, however, is that all predictions have been defeated by the sheer weight of the number of people pouring daily into the territory. Plus the fact that, when families are allocated a permanent home, they sometimes can prove difficult to dislodge, even when their circumstances have improved and they could well afford to move into private housing. Nevertheless, the admission from the Government this week that 13 units will continue to house families after 1997 will dismay the thousands who live in these squalid homes. After the outcry when Governor Chris Patten visited Kai Cheung a year ago, hopes were raised that the end was, indeed, finally within reach. But couples struggling to raise families in dreadful conditions now feel betrayed, and the only way to counteract this is to give them a realistic timetable for rehousing. Even the poorest conditions are tolerable when there is a definite end in sight. The Government should develop a rehousing strategy within a time limit which it can genuinely meet, and announce this by the end of the year. That will ensure these units truly become the museum pieces they should be.