Yeah, I was just thinking that everything I've read about Britain, probably from 700-900 hinted at pitifully small armies, but I think I understand what your saying.

Before I start, I must say that large armies are not the only way to challenge the civilised world. You can take civilisation apart with small and numerous raids just as well as with large campaigns.
Which leads to a much more important question. Could a couple guys with couple modern gatling guns and infinite ammo take out an entire legion?