Piston : My father forgot his passport on a business trip to Germany, by ferry. P&O agreed to carry him (not so easy on an aircraft, as they are responsible for repatriation if entry is denied) and the French immigration accepted his driving licence (of course without photograph). So you have to get the carrier to agree to carry you, then immigration the other side to accept you.
It is not quite correct to say that we are able to travel without passports in the EU. Although it was, I believe in the treaty of Rome, it has only been implemented - under the Schengen agreement - between certain coutries, not including the UK (probably because of PIRA).