Is Milton's Paradise Lost an epic?

Paradise Lost is also epic in two senses: one, as an allegory of the mind, and particularly the way envy causes harm, but also is necessary for creativity; and two, a political allegory dealing with issues that occurred in Milton's England. 

Milton was alive during a time known as the interregnum, which was a time when England didn't have a king or queen.  Milton was a strong political voice, and even imprisoned for beliefs.  He was probably very fortunate not to have been killed.  He was strongly against reinstating a kingdom. 

Psychologically, or perhaps spiritually, the text could be perhaps termed a map of the mind, like Dante's Commedia, or Blake's works. 

It is not true that Paradise Lost is the only British epic, as The Fairie Queene, rarely read, but something Milton would have read and admired, and also Blake's works Milton & Jeruselem.  Of course one wonders if the early British epic Beowulf counts.  Perhaps some of Wordsworth also counts.

Satan is in a sense the epic hero - but he is flawed and mistaken and causes the state we are now in - outcast from eden.  Interpretations of this, however, are markedly different.  Some who are religious argue Satan is evil.  Others, however, look at Satan and Eve as having done good for helping humans become active - without eating from the tree of knowledge, man would be sort of a vegetable.  Thus, the idea might be, without envy, we humans would perhaps be very passive and not learn.  Some even argue that whatever god is really wanted us to eat from the tree; after all, if you give someone free will, but forbid them something - well...

Thus, perhaps we can argue that this epic is about a tragic hero that seemingly unlike Beowulf we are supposed to hate, but that works like Beowulf to do some evil or injury to man.  Beowulf as an epic hero has to be read ironically unless we read it as coercive and propagandistic. 

Perhaps thus it also seeks to undermine the blind patriotism or nationalism created by the Beowulf and similar epics, and instead create an epic accepting of the need for dissidence and learning. 

One of the beautiful poetic elements of Paradise Lost is its use of simile: Milton compares the acts of the devils & Satan to things in reality and history, and the implication seems to be that reality absorbs and conquers envy, or hatred.  Whatever humans do or create - even if it is evil - can be absorbed by reality and by good.  This receptivity is a beautiful feature of reality we might not see so well except for Milton's vision.