I separated from my husband a few months ago. The kids were meant to be going to his for a few days on Boxing Day, but when Tier 4 was announced he hightailed it out of London so he wouldn't be stuck here. He's gone to stay with his mum in Tier 3 - pretty sure that's not allowed, esp since his mum's already bubbled with his sister. He will have travelled through central London last night on packed trains, and he's planning on coming back by train some time after Christmas, giving him ample opportunity to pick up the virus. I'm wondering whether I should ask him to self-isolate when he gets back before seeing the kids - not only do I not want them getting sick, I don't want them inadvertantly taking the virus to school or infecting our support bubble, one of whom is vulnerable and won't be able to have the vaccine if/when it's available. We also take public transport to school (no choice there) and DD and I are both asthmatic. Would welcome opinions!