As Theresa May was just ending her year in a better place than her team could have imagined, her deputy has been forced to depart from government, despite his continued insistence that he has done nothing wrong.
Damian Green has never been a politician with a huge public persona, or even a hugely well-known character.
But he was an extremely important ally of Theresa May. Not just a political friend but a genuine one, close to her for decades.
The government, so the joke in Westminster goes, has become "weak and stable", with number 10 taking back some control of the agenda in recent weeks.
So it is not likely that Mr Green's exit will suddenly unleash another bout of turmoil.
But the prime minister clearly took this decision very seriously.
His friends in government had believed that he would have been cleared, with one minister telling me today, "he'll be fine".
After the prime minister received the initial report on Monday from the Cabinet Office official Sue Grey, who found flaws in his account, Mrs May asked for further advice, calling in her independent adviser, Sir Alex Allan.
He then, in turn, concluded that there had been breaches of the rules. With that, Mrs May had little choice but to ask him to go.
But just as Damian Green's friends say it is a disappointment for him, still insisting that he has done nothing wrong, so too it is a political blow for the prime minister.
She is a politician who guards her views, her own persona very closely. To lose one of the few who understood her, who she trusts, leaves her a lonelier figure tonight.