HC Deb 09 July 1980 vol 988 c171W
Mr. Marlow

asked the Secretary of State for the Home Department whether he is likely to have information in the future which will enable him to make an estimate of illegal immigration and overstaying; and, in which case, what form that information will take.

Mr. Raison

We are aware of no basis on which any reliable estimate of the number of people in the United Kingdom illegally could be made. By the nature of illegal entry it is impracticable to measure its extent, but we are studying whether, when the new computer system is fully operational, it might be possible to use it to obtain information that could be used to estimate the extent of overstaying.