Our Brexit fate is in the hands of France's President Emmanuel Macron - which is "not a wholly comfortable state of affairs," in the euphemistic words of a minister.
What this minister means is the prime minister and her close colleagues are a long way from being convinced Macron will underwrite EU president Donald Tusk's proposal for the UK to be granted a year's delay to Brexit, with a break clause to allow us to leave the EU earlier if all the political and legal niceties can be completed earlier.
They believe - rightly or wrongly - Macron has three serious reservations with conceding such a longish and relatively unfettered extension.
1) Macron sees merit in punishing the UK for Brexiting, in order to deter populists in other EU countries from pursuing agendas to extricate their respective nations from the EU.
2) Macron fears Jacob Rees-Mogg speaks for a number of the candidates to succeed Theresa May - and notably Boris Johnson and Dominic Raab - in urging the UK to abandon the "duty of sincere co-operation" with other EU members, were our membership of the EU to be extended. On Friday, Rees-Mogg said the UK should "veto any increase in the budget, obstruct the putative EU army and block Mr Macron's integrationist schemes".
3) Macron has a penchant for big ideas and ambitious projects - which means, UK ministers fear, he would be profoundly uncomfortable with any Brexit delay that was a muddling through rather than for an explicit purpose.
This leaves the prime minister in the embarrassing position of needing to urge amity and leniency on Macron, when she meets him tomorrow evening.
She will be hoping she'll have something tangible to tell him about a possible Brexit entente with Labour - though the Government is torn between the imperative of demonstrating the talks with the opposition are sincere, and the risk a detailed agreement would in practice be a target for both Tory Brexiters and EU Governments to blow up. Ministers and EU officials see Labour's official Brexit plan as cakeism of the most cynical and unrealistic kind - because they don't see how it is compatible with Labour's pledge it would end free movement of people.
Theresa May will also have to somehow agree a formula with Macron and other EU leaders that would commit both herself and her successor as PM not to do as Rees-Mogg urges, namely to cynically disrupt the smooth functioning of the EU, until a better Brexit is agreed. Which if it can be done (not obvious) would mean the UK being shackled with an inferior class of EU member during whatever membership extension is offered us.
Just to remind you, a Brexit delay requires the unanimous agreement of all EU members states (including the supplicant, the UK). And France is probably the only EU member, and Macron the only EU leader, empowered enough by a sense of EU ownership to exercise the veto, at the UK's expense.
I am now told by reliable sources that the most likely outcome of the special summit on Wednesday is another kicking of the Brexit can down the road, but only till a bit after the elections for the European Parliament at the end May - so that a potential no-deal Brexit cannot infect those elections, but not so far that all pressure to sort Brexit dissipates.
Just possibly the delay will be closer to what May has requested (end June) than what Tusk suggested (a year) - presumably to reduce the potential for a new PM (maybe called Johnson) to wreak what EU leaders would view as havoc.