22 May 2020
This notice provides the latest information on the error in the 2018-based national population projections, and the approach we will be taking.
The error was caused by incorrect processing of cross-border flows between Wales and England, resulting in the projected mid-2028 population for Wales being approximately 65,000 too low, and that for England being approximately 65,000 too high.
Following discussions with our partners in the devolved administrations, we have agreed the following:
We will publish corrected projections for Wales.
We will not change the projections for England, where the much larger population size, combined with the inherent uncertainty around the projections and underlying estimates, means a correction would not be statistically beneficial.
For the same reason, we will not change the 2018-based subnational population projections for England.
There will also be no change to the projections for Northern Ireland, Scotland or the UK as a whole.
We will publish an explanatory note with the correction, including advice for users.
We will replace all the open data projections for Wales by Thursday 11 June, making the new data available for analysis. We will publish the replacement summary tables by the end of June.
We apologise for any inconvenience caused by this error.
18 May 2020
We have identified some processing errors affecting the 2018-based national population projections. This mainly affects the flows between England and Wales. The impact of this is major. We will be replacing the product. We are consulting with our partners in the Welsh, Northern Irish and Scottish governments, and will provide a more detailed statement on our approach.
Note that because this issue only concerns flows between different parts of the UK, there is no meaningful impact on our projected totals for the UK as a whole.