A theoretical question I am curious about.
Many times I have crossed Schengen land borders. I've had the good fortune to never be fully stopped and searched whilst doing this but I always had my passport with me just in case. There have been occasions where I've momentarily forgotten it and nearly missed trains due to having to run back to wherever I am based to get it.
I am curious however, in a worst case situation, what would happen to a UK citizen who gets stopped by the border police when crossing between Germany and France (or elsewhere in Schengen)?
Would a driving license be enough (this counts as ID for the purpose of legally being required to carry an ID within most European countries, though it is not a valid travel document)?
What if you are also missing this?