The original record would not be discarded or destroyed. In the case of a GRO register it would be on a page that contained up to 9 other entries with 10 more on the back, so it could not be physically separated anyway. It would just not be produced as a certified copy.
In the case that I mentioned where a child was registered by the 'adopting' couple (well before 1927), and then the birth mother gave the correct information, the GRO would not produce the original entry, but I have a vague recollection that they said it was because the records was less than 100 years old at the time. I haven't tested this out, but it may be that an older superseded original could be produced, and it is always worth asking the local Register Office. The worst they can do is refuse, so you are no worse off. Again, something I will try to find out!
Mean_genie
