Well that sent me down a random Wikipedia dive.
In the United Kingdom, stop signs may only be placed at junctions with tramways or sites with severely restricted visibility.[30] Until 2016, each stop sign had to be individually approved by the Secretary of State for Transport.[31][32] This requirement was removed by the 2016 amendments to the Traffic Signs Regulations and General Directions;[33][34] the responsibility for approving stop signs now lies with local authorities
I remember Tom Scott did a video about a really dangerous junction with one a few years ago. The road layout there has now been fixed so it's not needed.
I've never seen one in the wild though.

They had a $14.5 billion debt of as of march last year. Servicing that at the super low interest rates of the past decade was so well and good, but that time is over, and now those lenders want their pound of flesh.