Al Murray is actually an Oxford Graduate, a Master of Arts in Modern History.
He used to have bit parts in many fringe comedy shows, however, his characterization of the 'Pub Landlord' is what he is mostly known for, it has kind of stuck and become his trade mark.
The following from Wiki kind of sums it up.
His character the Pub Landlord is a stereotypical, right-wing British patriot advocating a dislike for anything "un-British".
You cannot help but laugh at his attempts to put the world to rights in a completely politically IN-correct manner.. Almost like a modern day Alf Garnett.
Last night the Stock Market, and that most terrible thing 'career politicians' were in his sights. Just brilliant.