Ancestry has released today UK Medical Registers, 1859-1959.
This database contains annually published books listing all of the names of doctors who were licensed to practise in the United Kingdom and abroad from 1859-1959. Also included are foreign doctors who qualified in Britain.
Be aware that the registers have only been digitised on 4 year intervals. In addition to names, the registers also list each doctor’s residence, qualification, and date of registration. there is no other biographical information so you will need to roughly know where and when they were practising beforehand especially of they had a common name.