Totally agree with Redsnail - it's mainly a LANGUAGE issue (but then again I'm biased since I'm foreign).
You guys ever heard of freedom of movement within the EU? You cannot legally restrict some Continental guy/gal's right to apply for jobs in the UK (not counting the Irish, since they all seem to work for Ryanair) - no more than you can do it the other way around.
Oh, and by the way, another good reason is that there simply aren't any flying jobs around in Germany/France/Belgium/Scandinavia etc. at the moment.
Cheers