It’s supposed to be three households in a bubble, and no mixing outside that.
So if we visit MIL on Xmas day, and she then visits BIL and his family on Boxing Day, that is it. None of us are supposed to see anyone else indoors for the rest of the 5 days.
Do people generally get this? I don’t think it’s been all that clear in the government comms, and seems like loads of people are going to break the rules, and we’ll see a huge number of cases among the elderly in January.