Probably to avoid being picked up later by the Police on some spurious grounds.
https://www.theguardian.com/technology/2023/dec/20/police-to-be-able-to-run-face-recognition-searches-on-50m-driving-licence-holders
One of my best photos - so I might as well take the opportunity to post it! This was the 'Fight For the Fox' when Cameron tried to have a vote on making hunting lawful again. And then, when it became clear that he was going to lose the vote - he pulled the debate on the morning it was going to...