Also, in some countries one is suppose to carry acceptable ID at all times. For a person who is simply visiting and travelling around, a passport is obviously the most readily acceptable form of ID that there is. A driving licence issued by an EU country might suffice in those EU countries as have this requirement. As the UK has no national identity card, this option is not available to British citizens.

The chances of being randomly asked for ID in one of these countries are small, but it does happen – especially near (not necessarily at) border areas sometimes, though it could happen anywhere.