but instead it's another damaging step for the prime minister after a bruising couple of weeks. 0ur political correspondent, nick eardley, reports. westminster has packed up for christmas, but it's events from this time last year that are continuing to cause controversy. simon case is the man the prime minister asked to look at allegations of rule breaking at parties. but yesterday it emerged there had been an event at his own private office. emails that invited people to a christmas party, which it emerged yesterday was a quiz. the cabinet secretary didn't attend, but he did speak to staff as he left — and last night it was announced he would stand back from the enquiry. another top civil servant, sue grey, would complete the probe. it's incredibly hard to believe nobody in government knew these parties were happening, and there's a huge amount of evidence now, so i do believe that the investigation sue grey is going to be leading up,