As far as I can recall the population of the UK has hovered around 55 million since the early 80s at least, but this number doesn't seem to make sense to me. I'm reminded of a March 2020 London Evening Standard headline saying that half of the adult population of the UK had been vaccinated and the headline gave 55 million people as the total for that number, which gave me pause for thought.
The UK population is 67 million today - and has been growing consistently year on year since the early 00's. It did hover around 55-58 million between 1970 and 2000 though.
