Theresa May faces a make-or-break period as she battles to keep her premiership on track until Parliament's summer recess.
MPs will drift away from Westminster and its febrile atmosphere when the Commons rises on July 24, potentially giving the Prime Minister some breathing space - but further challenges remain in the autumn.
Here are some of the key hurdles facing the Prime Minister over the coming days, weeks and months:
The Taxation (Cross-border Trade) Bill being debated on Monday will be the Tory Brexiteers' first show of strength since the Chequers plan which would keep the UK closely tied to EU rules on goods and food.
The Government could be forced into a compromise to avoid a damaging blow to the Prime Minister's authority. Further tests will come as the Trade Bill is debated on Tuesday.
A possible "Geoffrey Howe" moment
Boris Johnson, who quit as foreign secretary warning that the Chequers plan would leave the UK as a "colony" of the EU, could make a personal statement in the Commons.
He used a Daily Telegraph column to ominously say "I will resist - for now - the temptation to bang on about Brexit".
A Commons statement could have echoes of Geoffrey Howe's devastating resignation speech after quitting Margaret Thatcher's Cabinet in a row over Europe.
Tory conference and European Council
If the Prime Minister survives recess, she faces a tough autumn, with the Tory Party conference in Birmingham from September 30 - where she will hope to exorcise memories of her disastrous speech at last year's gathering - followed by a summit of European leaders on October 18 in Brussels where she hopes the details of Brexit will be agreed.
The threat of a coup against her leadership
Disgruntled Brexiteers need to muster 48 MPs' signatures to secure a vote of no confidence, and 159 Tories' votes to oust Mrs May and trigger a summer-long battle for the leadership, with possible candidates including Mr Johnson, Jeremy Hunt, Sajid Javid and maybe Jacob Rees-Mogg.
A full-blown three-month contest would produce a new prime minister - and potentially an entirely different approach to Brexit - just weeks before the crunch Brussels summit in October.
Selling the Chequers plan
If Mrs May holds on as leader and manages to rally her troops behind the Brexit plan agreed by the Cabinet at Chequers, she still faces the tough challenge of winning the EU over to her proposals.
The PM has mounted a diplomatic charm offensive over recent days to sell the plan to EU leaders like German Chancellor Angela Merkel.
But the Brussels establishment is still likely to baulk at provisions which it regards as "cherry-picking" the advantages of EU membership while dodging obligations.