EU Regulation 883/2004 provides for, and supports, the free movement of people within Member States. This Regulation is binding on all Member States and must be implemented as directed. It does not allow for any discretionary element in establishing entitlement. It is the link with the social security system of a Member State which makes any particular Member State liable for a persons's healthcare costs in the country where he/she is residing. Frontier workers, i.e. persons who live in one Member State but pay social security contributions in another, are also entitled to receive their healthcare both in their State of residence and in the State where they are employed and paying social insurance contributions. In this regard, a person resident in Ireland who is working in Northern Ireland and paying their contributions there, would normally be entitled to receive healthcare services in Ireland at the cost of the UK, provided they are not subject to Irish social security legislation. Persons in this category are entitled to full eligibility and receive a medical card on the basis of EU Regulations as evidence of their entitlement.
The EU Regulations allow for two or more States to agree alternative arrangements for reimbursement other than those laid down in the Regulations, or to mutually waive reimbursement altogether. The reimbursement arrangements under the Ireland/UK bilateral agreement cover such persons as temporary visitors between the two countries, pensioners of one country and their dependants residing in the other country, and the dependant family members, residing in one country, of persons employed and residing in the other country. Costs in relation to frontier workers, and their dependent family members residing in the same country as the worker, are mutually waived. Under the terms of the agreement net liability between the two countries is calculated on a lump sum basis rather than an individual basis. By far the biggest part of the payment received from the UK on an annual basis relates to the provision of healthcare to UK pensioners residing in Ireland. An amount of €220 million was received from the United Kingdom in 2013.