As part of the 2003 Accession Treaty and to alleviate concerns about the negative impact that the full application of EU law on free movement of workers could have on the labour markets and the social situation of the EU's then 15 Member States, a seven-year transitional period was agreed during which countries could gradually introduce the free movement of workers.
Osana 2004. aasta ühinemislepingust lepiti kokku seitsmeaastane üleminekuperiood, mille jooksul võisid liikmesriigid järk-järgult loobuda piirangutest tööjõu vabale liikumisele.