Its actually quite difficult to know. It has been taken as a simple axiom that Brittania was a Romanised province, and that the Roman presence improved life in Brittania. There are questions, however. Why was there such a large military presence throughout the Roman period, for example? Archaeology has tended toward finding Rome, and so Roman villas, temples, toens etc have been given, perhaps, more emphasis than they merit. The great majority of the inhabitants of the province still lived in pre-Roman type round houses and small farmsteads. Sure, 'Roman' goods entered these households sometimes, but can we really claim that having Roman type pottery made you Roman?
A couple of interesting books on this are 'An Imperial Possession: Britain in the Roman Empire, 54BC-AD409' by David Mattingly and 'UnRoman Britain:Exposing the Great Myth of Brittania' by Miles Russell and Stuart Laycock.
They tend to raise more questions, rather than give answers, but then I think the 'standard' history of Roman Britain, and its collapse, is built upon some false assumptions and sweeping classifications, in my humble opinion.
Bookmarks