Well the Albion from my understanding is an old name for England, an England that celebrates the beautiful things about this country such as its gentry, romantic poetry, music and the countryside. This vision the libertines had was to remind people about a forgotten England as well as celebrating all the good things about it. Hibernia is the Irish version and there is a forgotten Ireland too that poets such as austin clarke wrote about. One of his poems, The Lost Heifer, is supposedly a reference to Ireland. The Libertines analogised their dream as a mission, en route to Arcadia, a sort of utopia.
in my own mind i think it is frightening that pete might have taken this concept too far as an opium smoking youngster, and i think he believes that the idyllic nirvana is found via drugs, but who knows. There is a lot of debate on it i suppose, and much to be said and pondered.
this is what i conclude from what i have read because i am passionate about this band, everyone who knows me can see it.