http://blogs.channel4.com/factcheck/fac ... ions/22942
and
https://ukconstitutionallaw.org/2016/05 ... -a-brexit/
According to these legal commentators:
It is clear that EU law and the EU treaties are distinct from many other international treaties in the extent to which they give individuals rights, ‘which become part of their legal heritage’
a crucial question of the Brexit debate is what happens to these rights if the UK withdraws from the EU? Post-withdrawal, EU law would cease to apply in the UK, meaning not only would the EU treaties cease to apply, but any national law implementing EU law would have to be repealed, amended, or possibly retained. So the legal source of many, or even most, of these rights would be removed
The crucial question therefore is whether rights already exercised under EU law (such as the rights of other EU citizens currently living and working in the UK, or of British nationals currently living and working elsewhere in the EU, without the need for a residence permit, work permit or visa) would be legally recognised as ‘acquired’, and still enforceable after a Brexit?
Art 50(3) TEU, which concerns withdrawal from the EU, provides:
‘the Treaties shall cease to apply to the State in question from the date of entry into force of the withdrawal agreement or, failing that, two years after the notification referred to in paragraph 2, unless the European Council, in agreement with the Member State concerned, unanimously decides to extend this period. ’
But Article 50 makes no specific mention of acquired rights. Nor does any other provision in the EU Treaties set out any explicit rules on protection of acquired rights. There is no legal obligation under the EU treaties for them to be taken into account.
Article 70.1(b) Vienna Convention provides that termination of an international 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 crucial point is that the reference to ‘the parties’ in Article 70 is a reference to the parties to the treaty – i.e. States. Article 70 does not directly address individual rights. The International Law Commission, in its commentary on the scope of the identically worded predecessor to Article 70.1(b) (Article 66 draft Vienna Convention) specifically rejected an interpretation that it gave rise to acquired rights:
‘… by the words “any right, obligation or legal situation of the parties created through the execution of the treaty”, the Commission wished to make it clear that paragraph l(b) relates only to the right, obligation or legal situation of the States parties to the treaties created through the execution, and is not in any way concerned with the question of the “vested interests” of individuals.’
absent a Withdrawal Agreement which gives give clear protection of acquired rights, existing national, EU and international law does not offer a great deal of protection. So the content of the Withdrawal Agreement would be crucial. And in order to protect British citizens’ acquired rights in such an Agreement, reciprocity would be necessary (i.e. the UK would have to offer similar protections to those from other EU states). Otherwise UK citizens may sacrifice their current rights under EU law in the cause of British isolation.