Could expats be barred from EU healthcare and benefits?
It's possible, but unlikely - not least given that it would open the door to retaliatory measures from the UK, which hosts its own share of expats from European nations. There are as many as three million EU nationals living in Britain.
British expats can also claim to pay their own way in Europe, as the UK paid £674 million in 2014-2015 to other European countries for the treatment of UK nationals.
However, the UK received just £49 million from other European nations in the same year to treat those from other countries residing in the UK.
Could expats be deported by EU members?
Almost certainly not. First, there are numerous political reasons for EU states not to do such a thing, including the treatment of their own, numerous, nationals living in the UK.
Mass expulsions of citizens from another developed economy would also startle foreign investors and potentially cause economic turmoil in the expelling country.
Expats would also enjoy significant legal protections that would apply after Brexit.
Many lawyers argue that British expats living elsewhere in the EU at the time of Brexit would have individual "acquired rights" under international law.
This is based on the Vienna Convention of 1969, which says that the termination of a treaty "does not affect any right, obligation or legal situation of the parties created through the execution of the treaty prior to its termination.”
The House of Commons Library says that "withdrawing from a treaty releases the parties from any future obligations to each other, but does not affect any rights or obligations acquired under it before withdrawal."
In other words, Brits who have already exercised their right to live in EU states can expect to keep that right after Brexit. One important point though: this only applies to people who have started expat life in the EU before Brexit.
After Britain leaves, Brits’ ability to live and work in EU nations will depend on new agreements the UK negotiates with those nations.
Source: The telegraph March 2017