I'm not aware that any specific proposal has been set out.
As
@Gloster says (correctly IMO) the problem is that it's clear that those behind the proposal, including the Honourable Member for the 18th Century, are very much opposed to
Imperial measures and I wouldn't put it past them to try to ban their use. It's instructive that the consultation document (
link) contains several statements of questionable veracity:
- The UK officially adopted the metric system in stages between 1995 and 1999. [The UK adopted metric in 1965]
- While consistency in measurement supports fair trade and empowers consumers there has been consistent opposition to the current law on units of measurement by some traders and consumers who consider it to be overly prescriptive and an unnecessary restriction on freedom of choice. [The use of "some" in this statement implies that it is more of an issue than it is. "Few" would be more accurate, especially since there is no prohibition on displaying Imperial measurements.]
- The UK’s exit from the EU has created an opportunity to review the law on units of measurement for consumer transactions and to take back control of our measurement system so that it better reflects the needs of British businesses and consumers. [Perhaps I imagined the existence of the BSI]
- The purpose of the review is to identify how we can give more choice to businesses and consumers over the units of measurement they use for trade, while ensuring that measurement information remains accurate. [Again, businesses are perfectly free to trade using Imperial measurements, removing the requirement to also display metric measures actually reduces consumer options and increases complexity - I've measured in metres but the vendor only sells in feet.