Are imperial measures even still taught in schools in the UK?
No, that's why it's possible now, because it's pretty irrelevant. And if some old gadger wants to sell his black puddings in pounds on Bury market and his doddering old customers like it who cares? It will be absolutely gutting for him to find his multi-million pound export wagon being turned back at Calais customs though.
Of course it could be the start of a genuine reversal of metrification but is there anyone here actually dim enough to consider that's going to happen? You can make your own mind up on that one.