Leading article: Yes to an amnesty, but not yet

The Commons Home Affairs Committee used some colourful language to describe the backlog of failed migrants who remain in Britain illegally. Its latest report said the figure was equivalent to the population of Newcastle-upon-Tyne. The committee chairman, Keith Vaz, accused the UK Border Agency of creating something akin to the Bermuda Triangle, that was easy to get into, but impossible to get out of. A Conservative chairman might have been still more damning.

It is now six years since the then Home Secretary John Reid, described the immigration directorate as "not fit for purpose", and two years since the Coalition came to power, promising not only to reduce net migration to "tens of thousands", but to get to grips – finally – with the backlog. Clearly, this is not happening, or if it is, then it is happening too slowly to make much difference. And it is this sense of always running to catch up that raises once again the question of an amnesty. Would it not be more realistic, more honest, and just better for all concerned to concede that those currently in Britain illegally are unlikely to be forced to leave, and give them the chance to live, work and pay their taxes as citizens?

The answer has to be "yes, but". Amnesties have a habit of perpetuating themselves, encouraging others to try the illegal route in the hope that they might in time become legal, too. So before an amnesty is announced, the Government must be able to convince voters that the borders are not as porous as they appear and that the UKBA is in a position to guarantee that the old backlog will not just be replaced by a new one. Clearly, at present, it is not.

But the other precondition must be a reliable record of those leaving, as well as entering, the country – and that means that exit controls, abolished in 1994, must be reintroduced. For years, ministers have said that the planned e-borders system was the solution. Now that e-borders seems to have gone the way of other government computer projects, exits as well as entries must be logged. Who knows, the data might show that the backlog is not as far out of control as the Home Office committee fears.