The BBC (online) Magazine has had some really interesting English Language articles recently, including this one on 'Britishisms and the Britishisation of American English'.
However, it wasn't until I read this article on 'The shared language of politics and sport' that I came across the Hail Mary pass, which probably says more about my British parochialism than about the prevalence of the term. For fellow Brits, a Hail Mary pass is a long forward pass made in the closing stages of an American Football game. Chuck it - say a Hail Mary - hope someone catches it in the end zone. That's the basic idea.
"Stepping up to the plate" has become something of a cliche in British political discourse. Somehow I can't see the Hail Mary pass catching on in the same way.