From Wikipedia:
A blue plaque is a permanent sign installed in a public place in the United Kingdom and elsewhere to commemorate a link between that location and a famous person, event, or former building on the site, serving as a historical marker.
This is one such Blue Plaque, commemorating the first use of Penicillin as an antibiotic to treat infections at the Radcliffe Infirmary.
I see these while cycling every now and then but seldom have the opportunity to slow down and read them. I really should make an effort to do so, they are fascinating!
Imran Idris 