A hard Brexit would involve full immigration control with the government determining whether to introduce a new immigration system for EEA workers or use the current Points Based System which currently applies to non EEA workers. (lawyer-monthly.com)
The guidance on the new Points Based System (PBS) is replete with warnings that the rules on entitlement to remain may be changed in the future. (newlawjournal.co.uk)
Adapting the current Points Based System applied to skilled non-EU nationals is one possibility but this will only provide sufficient access to middle and lower skilled EU workers if a currently unused part of the system (known as «Tier 3») is implemented. (foodmatterslive.com)