Professor Siobhán Mullally:

I am going to talk about the possible implications of a UK withdrawal from the EU with regard to free movement of persons. The debate concerning the UK's membership of the EU and a possible withdrawal has centred to a considerable extent on the free movement of persons. Proponents of reform argue that the current EU legal framework does not provide adequate safeguards to ensure the free movement of persons without overburdening member states' public finances.

The free movement of persons is protected in the EU treaties and also in the charter of fundamental rights, where we also see a protection of access to social security benefits and social advantages. Also of relevance here is the 2004 citizens directive. Of the proposals to reform current EU free movement law as part of a possible precondition to the UK's remaining within the EU, several of the proposals that have been raised would require a treaty amendment and unanimous approval by each of the 28 member states, followed by enactment into domestic law. Other proposals do not require such change.

At the outset, it should be noted that one of the key concerns for Ireland will be the continuing functioning of the common travel area. Movement between Ireland and the UK of EEA and non-EEA nationals is likely to be significantly affected should the British exit proceed. As recently as December 2011, a joint programme of work was agreed to strengthen the security arrangements of the common travel area and to provide a framework for a more strategic approach for this co-operation.

Given this quite recent initiative and the existence of the common travel area arrangements, albeit relatively informally for a significant period, it seems likely that the UK would wish to treat Irish citizens differently from other EEA nationals should withdrawal proceed.

If withdrawal were to proceed, there would be a number of possible scenarios, which have been discussed. There are uncertainties associated with each. One possibility would be that the United Kingdom would remain as a member state of the EEA and continue to participate in the Single Market with a status similar to that currently enjoyed by Norway, Iceland and Liechtenstein, for example. This would require little change to free movement rights but is unlikely to be an option given that much of the debate on withdrawal has centred on limiting free movement rights. Discrimination between EU citizens dependent on their country of origin is likely to be problematic as a matter of EU law.

A second possible scenario would be bilateral negotiations whereby the United Kingdom would negotiate bilateral arrangements with selected EU member states. This, however, would lead to significant fragmentation of free movement rights and could create difficulties, particularly for Schengen area states if all Schengen area members were not to be included in such bilateral agreements. As such, it is likely to be politically difficult for any individual member state to negotiate bilaterally with the United Kingdom.

A third option would be that domestic UK laws on immigration would apply, in which case we would see a repeal of the exceptions currently provided for EEA citizens. In such a scenario, EEA citizens and family members already in the United Kingdom may be permitted to remain - as permanent residents, for example. Those without rights to permanent residence, particularly jobseekers, would be easier to remove given that the current protections provided by free movement law would not apply. What we would then see would be the introduction of visa requirements for entry for work, study or family reunification. EEA nationals would effectively be treated as third country nationals are treated at present. A range of possible restrictions could be introduced, including visa requirements, linked, for example, to minimum income requirements, language skills and the supply of biometric information. We would see a phenomenon akin to the current five-tier points system that applies in UK immigration law being applied to EEA nationals. There is concern that this would lead to significant reductions in migrant workers, including highly skilled workers, coming to the United Kingdom. Any of these scenarios would be likely to have a significant impact on the operation of the common travel area between Ireland and the United Kingdom.

With regard to the possible reforms that are being mooted as a precondition to the United Kingdom remaining within the EU, a number touch on free movement. One covers access to social security payments, including a proposal limiting access to housing benefits, social housing and tax credits for a minimum period, possibly up to four or five years. With regard to EU citizens who are categorised as workers as defined in EU law, a change in the EU treaties would be required. Therefore, it would seem unlikely to come into effect. For those who are jobseekers or do not meet the definition of "worker" or "former worker", this reform would be less problematic. The European Court of Justice judgment in the Dano case in November 2014 confirmed that limits can be placed on access to non-contributory benefits, including a requirement that the residence conditions of the citizens directive be complied with.

A related proposal would be that the UK Government would seek to renegotiate the principle of exportability so origin states would remain legally responsible for covering unemployment or non-contributory benefits that would, for example, be required by their own citizens for a minimum period.

There is some commentary that these changes would not lead to any significant changes in terms of movement of EU or EEA nationals and that they may actually lead to more vulnerable persons falling through the cracks of social protection. It could have a significant impact on UK nationals living in other EU countries. This, of course, is of significant concern to a number of countries, including Ireland, Spain, France and Germany, where the costs of providing health care are high and where the number of ageing UK citizens would be significant.

A second proposed reform would be in the area of rights to family unity and family protection. The right to private and family life is protected in the EU's Charter of Fundamental Rights and also, of course, under Article 8 of the European Convention on Human Rights. A proposal to impose restrictions on the entry of non-EU citizen family members in light of the Metock judgment could create difficulties and may be viewed as requiring a treaty amendment, at least with regard to those persons categorised as workers and former workers - those who derive rights from the treaties. Other proposals - for example, to link family reunion to minimum income requirements and language skills - have already led to some criticism from the European Court of Justice.

A third proposed area of reform relates to the possibility of limiting rights of entry for job seekers by imposing a requirement that an EU or EEA national seeking entry to the UK be in possession of a genuine job offer. This could raise practical difficulties, but also legal difficulties. Currently, an EU citizen can reside for a three-month period with a valid passport and without recourse to social assistance, and thereafter the right to reside is dependent on having sufficient resources and sickness insurance. Those EU treaty rights to free movement also apply to job seekers, which is particularly relevant here, so long as they have a genuine chance of being engaged in employment. It is likely that a treaty amendment would be required to effect such a reform, and this would be difficult given the protections of the right to private and family life in European human rights and fundamental rights law. Linked to that is a proposal that job seekers who do not secure employment within a six-month period could be removed. This also would lead to difficulties and would come into conflict with decisions already given by the European Court of Justice, notably in the Antonissen case.