The Government has released a policy paper on what would happen to citizens’ rights in the event of the UK leaving the EU without a deal, both for EU citizens in the UK and UK nationals in the EU.

Given that what will happen is still unknown, even the timeline for deciding that, all archaeology employers are encouraged to read it:

https://www.gov.uk/government/publications/policy-paper-on-citizens-rights-in-the-event-of-a-no-deal-brexit