The medical register.
General Medical Council (Great Britain)
London : General Medical Council,
"Comprising the names, addresses, and qualifications of medical practitioners registered fully or provisionally on January 1, together with the dates of registration of practitioners and other information concerning medical registration".
After 2004, the Medical register is published online only as the: List of registered medical practitioners.  See http://www.gmc-uk.org/doctors/register/LRMP.asp
Physicians
List of registered medical practitioners