Whatever exactly we decide a crash blossom is, we are surely going to want to agree with James Martin, of the Department of Statistics at Oxford University, that this is one:
May axes Labour police beat pledge
James notes that every single one of these six words can serve as either a noun (sample possible senses: fifth month; woodcutting implements; opposition party; constabulary; musical timing unit; commitment) or a verb (will possibly; performs chopping; work hard; oversee; physically chastise; give a promise). So we start with 26 = 64 different assignments of noun or verb status, and start sifting about for a coherent parse that gives us a meaning that could make sense in some context.
If some of us succeed in parsing it, that's quite remarkable. It's a singularly difficult one in isolation, especially if you're not up to the minute with British political news. To satisfy your curiosity about whether you parsed it correctly, go to this article in The Guardian.