Well, well, well, didn't this start all jolly hockey sticks? For those of you not familiar with the term, this refers to a plummy, upper-class, private school philosophy that we lower and middle class inferiors like to use as a social slur, when we're all just jealous of the lovely cars and houses these posh tossers all enjoy.
It all started very Notting Hill/Four Weddings as this group of middle-aged toffs meet in the country house they have borrowed from Mummy for the Christmas weekend. This had become something of a tradition, if you believe the invites and this collected group of what seem like ex-University chums who are all old enough to have children, whether they do or not, all take turns to display their own brand of frightful privilege.
It's like Enid Blyton's Secret Seven and Famous Five all grew up and met once a year to congratulate each other for just being themselves and to test out the lashings of ginger beer the host as made using only his feet, that he learned to make whilst on his gap year in a kibbutz in Palestine.
As time goes on and as festivities continue, it becomes apparent that there is more to this get-together than we at first imagine. While it is indeed a tradition, this will be the last time they carry it out. Something very bad is going to happen, and over the course of the last acts, we find out what.
Great acting, of course, even from Knightley whose acting credentials I've always had a problem with personally. The story is as little too laboured and could easily be captured as fully in half the time.
Less horror and more tragedy if we're honest with ourselves. Don't be fooled into thinking this is anything but. Home Alone could be seen as dark, depending on your perspective, but even with its initial frivolity and hedonism on full show, there is no denying that this is a disaster just waiting to happen.
A tepid, drawn-out first act is more than made up for by the third, with a general sense of good-old fashioned English averageness in the middle. Still, worth a watch, despite that. Just for the ending if nothing else.