One reason I was quite happy with Brexit was the thought that we'd only be accountable to our own laws that have evolved over hundreds of years. Maybe not. ( Other benefits or not of Brexit have been discussed prior to and after leaving so I'm not going down that road ).
I read sceptically that Rishi Sunak is proposing a new law basically saying that anyone arriving in the country by small boat ( assume from France ) will not have the right to stay. However, this law may be blocked by the European Court of Human Rights. ( assume France ) So much for Brexit giving us legal independence!
Boat people will need to be detained (where?) and repatriated (where?). We've not been good at solving these issues so far, so what chances of doing so in the future?
Will it ever happen? Probably not.