[jimworcs]

All EU states remain sovereign nation states and have retained their right to issue passports and control their borders. There is no such thing as an EU passport.

However, all states within the EU are required by treaty to allow other citizen's of EU member states to live and work in their country (subject to certain restrictions). For example, countries can exclude those who pose a threat to national security or have criminal convictions for example. Also, some countries have placed restrictions on citizen's of accession states for a period of years.

My point is that the comparison with inter-state travel in the US is not valid at all... and each country has retained the right to control it's borders.

The Schengen agreement is an agreement by some member states to create a common border. Under this agreement, the first point of entry of a citizen becomes the border control for all countries which subscribe to the Schengen agreement. So, for example, if an Indian citizen enters France at Paris CDG, and passes immigration procedures, they will not have to go through the procedures again if they then flew to Frankfurt. However, the UK did not sign up to Schengen, and this means that anyone flying to the UK, regardless of where they are flying from, is subject to exit and entry checks and this includes UK citizens.

The agreement between the UK and the Republic of Ireland to allow travel without passport controls still stands, although some form of ID may still be required. As the UK does not currently have an ID card system, these means in practical terms the most useful form of ID is a passport or photo drivers license. The UK will have a voluntary ID card system from 2010 and this will allow travel to any EU country without a passport, if you have a valid UK ID card. (The ID card will be voluntary for UK citizens, but compulsary for new immigrants).

Hope that helps.