This reform would require co-ordination between the Ministry' of Interior Affairs and the Ministry for Information and Communication, and the adoption of new' legislation. Since internal moves are not recorded formally there, information from the National Health Service Central Register (NHSCR) and GP Patient Registers are used as a proxy for estimates of the population of England and Wales. This data is considered to be a good proxy for internal migration, since w'hen they move, most patients will eventually register w'ith a new GP.