Those interested in the front part of the Internal Market Bill (the part that cuts across the powers of the devolved Parliaments) should read this analysis by @ProfKAArmstrong of what it means in practice. https://www.parliament.scot/S5_Finance/General%20Documents/2_Briefing.pdf.

He gives two examples. One is the deposit and return scheme for containers. He argues convincingly that, though that scheme was likely compatible with EU law, it is very vulnerable to challenge under the IMB.

One central reason why that is so is the absence of environmental protection as a reason for departing from mutual recognition (and the messy interface between the mutual recognition and non discrimination principles).

Note also that even the “public health” justification is limited and piecemeal compared to EU law.

Bear all this in mind when you weigh up the current government’s claims that the Bill leaves devolved governments overall with more power than they had under EU membership.

On his 2nd example, minimum pricing of alcohol, his argument is to some extent overtaken by government amendments: see a further note here. https://www.parliament.scot/S5_Finance/General%20Documents/Briefing(3).pdf

But even there, the risk of successful challenge to further measures along these lines is significant.

The Secretary of State can deal with many or most of those issues by amending the Act: he has wide powers to do so, when he wants.

But that shows the fundamental asymmetry here: if the U.K. government - also the government - wants to make sure that the IM Act doesn’t disrupt its chosen policy, it just changes the rules. But and have to knuckle under the rules as written by the U.K. Govt.