Statistics on migration flows year by year within the UK are produced by the Office for National Statistics, the General Register Office for Scotland and the Northern Ireland Statistics Research Agency for migration within England and Wales, within Scotland and within Northern Ireland respectively. However, these flow statistics are not integrated across the UK. As there was a need for such integrated flow statistics at a sub-national scale known as NUTS2 for an EU sponsored project, the authors developed a synthetic estimate of migration flows for the calendar years 2000 to 2007 and the mid-year to midyear intervals 1999–2000 to 2006–07. The estimates were controlled by the migration flows published at NUTS1 scale from the UK wide NHS Central Register to which country specific flows between NUTS2 regions from the various patient registers were fitted. The gaps, flows between regions in different devolved territories, were filled by adjusting comprehensive flow data from the 2001 Census to the published NHSCR flows. Age detail was added only to the total out-migration and in-migration flows from each region using a fixed national profile of migration rates by age from the 2001 Census. The resulting time series of flow data provide, therefore, the three matrix faces of an origin-destination-age array for each time period. The paper describes the details of the estimation process and reports on some of the trends that the time series show.