Conspiracy theory time; there is no super infectious new strain. They realised that easing lockdown over Christmas would be a disaster but the cat was out of the bag, people wouldn't have accepted it being snatched back without good reason. Enter rumours of a terrifying "new strain", goodbye Christmas gatherings.
I'm not saying this is the case but... Well... It's not the most far fetched idea that's ever slapped my mind.
The timing is sus, and the amount of information they apparently have about the spread stats of this newly identified strain are oddly specific.