The Mountain Instructor Award (MIA) qualifies you to take people multipitch climbing anywhere in the UK. It does not cover winter climbing. It covers technical navigation, rope rescues, multipitch scenarios and requires a high standard of competence. You can also teach people how to lead climb.
This article details the remit of the award, how to register for it and what exactly it covers.
Read more at http://www.ukclimbing.com/articles/page.php?id=1913