Having traced my own family tree back to the sixteenth century, I am currently helping someone else with theirs, but we’ve hit a snag.
Turns out his own mother was adopted c. 1900, and he never knew this before (he was told this by a distant relative, and it is borne out by the fact that there is no record of her birth at the General Record Office, under the name she grew up with).
Trouble is, as far as I can gather, in the UK no formal adoption records were kept until about 1927, so I’m stumped. Closest I have managed to get is to find a couple (in the 1901 census) who were of suitable “adopting age” in the right area, with the right surname and father’s christian name as shown on the adoptee’s marriage certificate.
I wondered if anyone here might know where to turn next? Any help would be greatly appreciated. 
Julie