On the contrary, the post-Roman state of Britain still experienced attacks from Barbarian tribes even after it was no longer a part of Rome -- it was not "given over to the barbarians" like Doli makes it sound like.

the Western Empire basically said "fuck it, you're all on your own" to its far away territories (such as Britain), but these territories still maintained a Roman-esque style of government and persevered through an onslaught of barbarians to eventually become the feudal states we hear about in the history books.

If this discussion is about the 'gray area' in European history - the transition of Europe between the Roman Empire and the Feudal Era, General Doli is wrong.