Since Brexit, the UK has risen as a top-ranked country for attracting highly skilled workers and even surpassed the US in this metric. One of the main reasons for this change within the UK's workforce demographics is its migration policies. The UK removed its quota for highly skilled overseas workers and extended more generous post-graduation visas for international students, which increased the number of highly skilled workers seeking jobs in the UK. While these policies have encouraged migration for skilled workers, employers have been struggling to acquire visas to hire lower-skilled workers to fill the post-pandemic labor shortages.
See "Changes to migration policies have made the UK an increasingly attractive workplace for highly skilled international workers", Delphine Strauss, Financial Times, March 9, 2023