The UK didn't fall after losing a good chunk of their army and almost all of their heavy equipment in the Battle of France. It was still a defeat. In the Therm

The UK didn't fall after losing a good chunk of their army and almost all of their heavy equipment in the Battle of France. It was still a defeat. In the Thermopylae case, they failed at their intended objective (defeat the Persian army on land) and wasted a good-sized force. The fact that the defeat was set in stone the moment they chose the place and time of the engagement doesn't make it any less of a defeat. (Note that "the 300" is only counting the Spartiates i.e. citizens; there were a total of 1-2K Spartan soldiers, and many more forces from other Greek poleis.)