I don't wanna take on his argument for him, but I agree with the original statement: pawn. A piece that you sacrifice. Britain wasn't going to save Poland, but they were willing to use it as a reason to go to war with Germany. As well you'd expect. Going to war with Germany was an existential risk for Britain. They wouldn't do it to save Poland's ass, and I don't think you'd expect them to. So Britain must've thought it was just as well for them to go to war with Germany.