Insofar as Theresa May now has a coherent Brexit strategy at all, it seems to be to attempt to pass her deal next week with opposition votes, assuming the Speaker lets it return for a third “meaningful vote”.  This means presenting the choice before the Commons as her deal or No Deal.  But would she really be prepared to deliver the latter, or try to?

(Her means would presumably be to reject any long extension offer if her deal was defeated – if her fellow Ministers and Parliament would let her, which is another story.)

This site has a simple test. A No Deal Brexit would cause severe problems for Ireland and, sooner or later, deliver the very hard border that its government has worked to avoid.

So if Leo Varadkar and his fellow Ministers sound alarm bells soon, it will mean that they believe that the Prime Minister is set on No Deal.  If there is radio silence, then they think she will accept a long extension and, in the event of her deal going down for a third time, put a statutory instrument to the Commons which would remove the March 29 date from the EU Withdrawal Act.

It is of course possible that Varadkar and company may call it wrong – for example, by ringing those bells only to find that May eventually accepts a long extension after all.  But it strikes us that the Varadkar Test isn’t a bad one.  After all, he seems to know more about what the Prime Minister will do than members of her own Parliamentary Party.