The story of the British special migration statistics.

"This paper describes a new data set from the 1991 Census called the Special Migration Statistics. Before release for general use by the U.K. social science and geographic community, it was essential to understand and to thoroughly check the data. This paper reports on the structure of the database and the checks carried out to verify its internal and external consistency. Finally, the paper summarises the pattern of migration revealed by the statistics for two illustrative spatial systems: wards in a large northern city and regions in Great Britain." The focus is on internal migration.