I've taken a photo of the flower on this succulent almost every day, as a possible blip. But up to now it's always been crowded out by something else.
We're gradually developing a liking for, and a collection, of succulents. They suit us as they withstand a good deal of neglect. We bought this one in early summer, and up to now it has spent its life outside. It is clearly very happy (or of course it could be really stressed), as it very soon decided to sprout a side shoot, which we only gradually realised was a flower spike. It really is rather lovely.
We don't appear to have a name for this particular plant, but I think we'll need to bring it in for the winter - I doubt it is frost hardy.