In two little-noticed decisions, the England, Wales and N Ireland 2021 census will go ahead as planned in March but Scotland's is deferred until 2022 because of covid.

It is not clear why National Records of Scotland/Scot Gov analysed the risk of a 2021 census differently from the Office for National Statistics (for E&W) and the NI Statistics and Research Agency (for NI).

This is the first time since 1841, when the censuses first started to record individual names, that the decennial link between all UK-wide censuses has been broken.

Whether the Scottish delay is political or technical, it opens up a number of issues.

1. Directly comparable data on numerous social/economic issues will now not be available across the UK for 2021.

2. In particular, ONS, who prepare UK-wide census figures from the three separate censuses, will now not be able to produce definitive statistics for the whole UK in 2021.

3. This may seems an abstruse issue but census data is regarded as the gold standard in terms of accuracy and is used by government for a whole range of policy-making and allocation of resources (£ to you and me).

4. Presumably, ONS will have to use estimates for Scotland based on different information (other surveys, other gov't data sets etc.) to produce UK-wide statistics for 2021.

5. If the experience of 2011 is repeated, Scotland's results will anyhow take longer to produce than the other censuses, as well as now being a year behind them.

6. So until (I'm guessing) 2014 or even 2015, when 2021 figures can be interpolated from 2022 data, UK-wide population statistics will always have some uncertainty attached to them.

7. This will give plenty of scope for arguments over several years about whether Scotland is or isn't getting its fair share of UK resources for numerous government functions.

8. This in turn is likely to give grist to the mill of the nationalist narrative of being hard done by the UK (some will seek to do that whatever the figures suggest).

9. It will not be a productive use of anyone's time, and you have to wonder whether it was necessary at all.

10. So what I called an abstruse issue about the 2021 (now in Scotland 2022) census is likely to have very practical adverse consequences. End.