We don't need to have it enshrined in law as right now little to no ISPs outright prevent access to popular services but as you said zero-rating is slowly creeping in.
Until an ISP starts preventing universal access nothing needs to be done, zero-rating (while bad for competition) does not do that.
A good question would be why aren't the competition petitioning the government to outright ban zero-rating? Current EU law has zero-rating loopholes, it'd be up to a post-brexit government to close them. Perhaps it's not popular with current ISPs and their customers? I don't think a large survey on net neutrality has been done in the UK.
Until an ISP starts preventing universal access nothing needs to be done, zero-rating (while bad for competition) does not do that.
A good question would be why aren't the competition petitioning the government to outright ban zero-rating? Current EU law has zero-rating loopholes, it'd be up to a post-brexit government to close them. Perhaps it's not popular with current ISPs and their customers? I don't think a large survey on net neutrality has been done in the UK.