This says
http://www.guardian.co.uk/uk/2012/jul/19/olive-stone-pre-roman-britain
that we had a perfectly good town at Silchester long before the romans invaded.
And that some people there were even snacking on fancy imported olives.
Goes some way to rebutting the 'what have the romans ever done for us' answer at least. Like we were just padding about in the mud waiting for them to turn up and sort things out.
(Not that eating olives is like the height of sophistication and civilisation of course. Though I do prefer the green ones myself.)