Tricky....

Can the Prime Minister invoke Article 50 (see post dated 6th July) without parliamentary approval?  Well, yes, probably so.  The "royal prerogative" (by which the Government exercises authority from the days when the monarch could do what they liked, simply because they were the monarch) covers the conduct of treaties and almost certainly covers this point.  So, she can, but should she?  Ah, that's a different question. There are certainly calls for her not to proceed without a parliamentary vote, but the problem is that as far as we know, the majority of MPs are opposed to Brexit, and she may well struggle to get their approval for such a move.  It's a bit "devil and the deep blue sea" stuff, isn't it?