Is Arlene Foster bluffing in Brussels?

Is Arlene Foster bluffing in Brussels? It must be one of the worrying questions for Downing Street.

Earlier today the DUP leader was not prepared to discuss last night’s "warning shot" in the Commons, when her MPs didn’t back the government in a parliamentary vote. I caught up with her in Brussels and asked her if she thought the Prime Minister had got the message.

Bear in mind that yesterday her party was threatening to go further and vote against the budget later this month, if its concerns about the imminent Brexit deal are not met. “Such a lovely morning“ is all she would say to me...

Not such a pleasant morning for the Prime Minister who is trying to please the DUP, the European Research Group - the ultra pro-Brexit wing of her own party - and the EU. Can all three ever be satisfied with the terms of a Brexit deal? Discuss.

Back to the bluffing though, speaking to another Irish politician his morning, who said a deal is close but that the negotiations are “extremely difficult”, they wondered if Arlene Foster would ever follow through her threats to block a Brexit deal and bring down the UK government. She’d be ripping up her guarantee to support the PM in the commons. Why would a Unionist politician want to bring down a Conservative and Unionist government, lose the influence it has on that administration and risk the extra funding for Northern Ireland that the DUP received in exchange for agreeing to support the Tory minority government?

Can Theresa May risk calling Arlene Foster’s bluff? High stakes at high noon for these Brexit negotiations.

• Robert Peston: Will the DUP risk bringing down Theresa May?