There is an interesting discussion here about whether the UK ID card should double as a travel document. If it does, it may have to be insecure:
This is one of many reasons why lately there has been great consideration as to whether any UK ID card should also double-up as a travel document: if it were to do so, it would immediately be compromised by the ICAO requirements. It would prevent the UK designing a twenty-first century identity system without any of the compromises of the old paper world being present .