Theresa May's satisfaction over securing a deal on the first phase of the Brexit talks was certainly shortlived.
Less than a week after returning from Brussels with agreement on the Irish border, citizens rights and the divorce bill, her government suffered a humiliating defeat inflicted by members of the Conservative Party.
The EU (Withdrawal) Bill has been proceeding through a lengthy list of amendments with Tory whips managing to avoid outright defeat.
However, all that changed on Wednesday night when around a dozen Tory rebels voted with Labour, SNP, the Liberal Democrats and others including Lady Sylvia Hermon to deliver a stinging blow to Mrs May's authority and her efforts to steer a path through the factions within her own party.
Up until now we have heard much about the Brexiteers, those determined there will be no softening on the UK's exit from the EU.
The prime minister has been kept in check by these uncompromising figures and is constantly watching over her shoulder at leading Leave campaigners Boris Johnson and Michael Gove.
Wednesday's vote showed there is a substantial number of Tory Remainers who are worried about where Britain is heading and trying to rein in the more extreme elements in their party.
The margin of victory was slender - just four votes. But it is clear there are more MPs feeling uneasy about this process and they may feel emboldened by this week's unexpected outcome.
What it also demonstrates is there is a majority in Westminster against a hard Brexit, even with the DUP supporting the government.
Senior Tories are playing down the significance of this defeat but it could prove far-reaching in terms of the eventual deal with the EU.
Given that the referendum was a simple choice between leave or remain, with no detailed information on what that would mean, it is entirely appropriate that MPs have the opportunity to vote on what will be the final shape of the Brexit deal.
