But all that can also happen in the EU. I don’t see it as progressive whatsoever. Remainers appear to be blind to what happened with eg Greece when it defaulted on loans.Certain workers' rights are determined by the EU, and it protects those rights. That leaves governments with a lot of scope to grant or deny other rights.
I think that, within the next 18 months or so, certain rights that were previously protected by the EU are likely to be removed, watered-down or threatened by the UK government. Who can say for sure, but I think it's likely. That might include, among other things, working time, redundancy, any industry-specific rights, agency workers' rights.