Brexit protesters near Parliament in London. Photo / AP
As Theresa May steels herself for an almost certain vote on her leadership this week, she knows that winning would be only the start of a grim, month-long battle for survival.
Like a storm-battered ship, she must navigate the deadliest of channels, relying on fate alone to steer her away from the rocks. Several obstacles lie ahead, which will come at her thick and fast in the ultimate test of her famed durability. Her backbenchers, the DUP, the EU and Parliament itself could all bring her down.
Her worst case scenario would see her forced out as soon as Wednesday if, as expected, Tory Brexiteers summon enough support for a confidence vote.
To date, 25 Conservative MPs have confirmed they have written letters to Sir Graham Brady, chairman of the backbench 1922 Committee, stating they have no confidence in the Prime Minister and demanding a vote on whether she should stay.
If another 23 Tory MPs write similar letters, Brady is duty-bound to call the vote (party rules stipulate a vote can be triggered by 15 per cent of its MPs) and Brexiteers are confident that threshold is within reach.
No one would be surprised if Brady announced tomorrow that he was in possession of 48 letters. Tory rules state he would then have to hold a vote "as soon as possible". When Iain Duncan Smith was forced out as Tory leader in 2003, the confidence vote sealing his fate was held the day after the threshold passed.
Ever since talk of a confidence vote first emerged, Downing Street has sent out bullish "bring it on" messages to backbenchers, supremely confident that May will win and earn at least another year in office (the rules also state that 12 months must pass before another confidence vote can be held). Even amid the turmoil of the past week, it still seems unlikely that a majority of Tory MPs would vote against her (159 would be 51 per cent), but they might topple her even without a majority.
Like John Major when he triggered a "put up or shut up" leadership election in 1995, May will have a figure in her head for how many MPs she would need for a genuine victory. Winning by one vote would still surely constitute defeat, as it would mean that 49 per cent wanted her to go.
Assuming a confidence vote is held and May wins convincingly, the biggest dangers will still lie ahead.
Five Cabinet Brexiteers - Michael Gove, Andrea Leadsom, Liam Fox, Penny Mordaunt and Chris Grayling - will meet to discuss how they might force the Prime Minister to seek last-minute changes to the Withdrawal Agreement, which has already been locked down with Brussels. They believe changes can still be made, principally to give the UK a unilateral means of exiting the Northern Ireland backstop. If May refuses (which seems certain) she could face another day of multiple Cabinet resignations, which could make her position untenable.
An EU summit next Sunday presents another potential trap for May. While the Withdrawal Agreement is (as far as she is concerned) set in stone, the political declaration over the UK's future relationship with the EU, which will form the basis of a future trade deal, is still in flux. There is room for further concessions to Brussels in the vaguely worded seven-page future framework document shown to the Cabinet last week, and several member states are pressing hard to secure additional commitments on fishing rights and regulations. May could find herself facing yet another revolt if she concedes to more giveaways.
Should she still be in Downing Street in a week's time, she will face the "meaningful vote" on the Brexit deal early next month. The omens, so far, are terrible.
When she presented her proposed Brexit deal to Parliament last week, she faced hostility from all sides. In a three-hour grilling, it took almost an hour before an MP expressed any support.
If MPs are to be taken at face value, the chances of May winning that vote seem hopeless. While she can almost certainly count on the support of the 150 MPs who constitute the Government, and around 85 loyalists on the backbenches, she needs another 85 votes to secure a majority. With roughly 60 Tory Brexiteers, plus the Northern Ireland DUP's 10 MPs, insisting they will vote against it, May can only win if she gets the backing of scores of Labour MPs.
Government whips believe that when MPs face the harsh choice between May's deal or the probability of no deal at all (or even a general election, a Labour government and a second referendum), they will grudgingly fall into line.
That is May's biggest gamble, and as her decision to hold a snap election last year showed, gambling has never been her game.