One of the
titles held
ex officio by the
Archbishop of Canterbury.
This has nothing to do with biology; yes, the Archbishop is a primate in that sense too. The title refers instead to the Archbishop's role in the Church of England.
The Archbishop of York is known by the similar title "Primate of England".
SOURCE: http://www.xrefer.com/entry/417447