If May 1 2004 was the European Union's 'Big Bang' with ten new countries joining the bloc, then December 21 2007 is likely to be another milestone and a telling test for progress in an enlarged Club Europe. It appears certain that nine of the ten member states (all bar Cyprus) that joined in 2004 are set to join another exclusive club - the Schengen area.
For several years under Schengen, visa free travel and minimal border controls have been the norm within continental Europe and non-EU members Norway and Iceland. The exception being the UK and Ireland which opted out of certain conditions of the Schengen Agreement.
If Brussels gives the nod to all nine, mostly former Soviet states, the frontiers of a borderless Europe will be pushed further eastward to extend from Russia in the north to the Adriatic in the south.