'Two-speed' Europe means the development of closer cooperation among some Member States, pursuing objectives that are common to all EU Member States, as they are actually and precisely the objectives aimed at by the EU treaties. The idea is that the members of a smaller group would be both able and willing to go ahead immediately, while this would not be possible for all. The other Members States, each of them travelling at its own speed, would follow later. The differentiation between Member States would be temporary. In the past, transition periods and temporary derogations, frequently provided by accession treaties for new EU Member States, have been examples of such a concept. These periods have sometimes been quite long, but the derogations have been limited in time, at least in principle.