Plasters lose their stick, revealing the hurt underneath. And the fragile patch that was covering the Tory truce has been well and truly torn.

Just when Theresa May wanted to show the European Union that she could hold her party together to win, she lost.

And at home the prime minister has been shown in no uncertain terms that she simply can't count on the factions in her party to come through for her.

There were, and still are, suspicions among Eurosceptics that the prime minister doesn't really mean it when she says we'll leave at the end of March, whatever happens.

It's no secret that a significant number of government ministers would push as firmly as they could to stop that happening.

And on show in Parliament, an increasing determination to make that impossible.

That explains the demand from Brexiteers for reassurance that Mrs May is still willing to follow the existing law and leave, whatever happens.

But this is more than just a Brexiteer strop over no deal.

Brexiteer grievances

Brexiteers who have been involved in talks with the government about the so-called Malthouse compromise, a different EU deal proposed by MPs, are frustrated that No 10 has not been more full-throated in support for that proposal.

That concern was, it's claimed, part of the reason for abstaining in protest, which resulted in this latest defeat.

Government sources suggest Eurosceptics' grievances were rather hungrier than that.

Whatever the whole truth, it is plain that Mrs May's challenge is not just to persuade a reluctant EU that she can carry Parliament but to bring a party together that has precious little appetite to do so.

This is though, far from the end of this troubled journey. In less than a fortnight, MPs will vote again.