I never said it did. You initial question was "If my mom, a US citizen, was in England on vacation when I was born, would I be an English subject". The answer was yes, prior to 1983, you would be a British subject ( no such thing as an English subject ). I didn't say anything about being a natural born US citizen. As far as being a British subject, in the circumstance you presented, citizenship was bestowed automatically- there was no need to claim it.
Thanks for the clarification.