I'm increasingly of the opinion that the 'Boris is self-isolating' stuff is just another smokescreen. Firstly, the MP who apparently tested positive has a wife who is being shielded, which means, I would assume, said MP has been ultra-careful all along. This should, surely, reduce the likelihood that he'd test positive. I know, probability vs reality and all that, but there's a whiff of improbability about this scenario.
Secondly, many of us have been working perfectly effectively from home, for months. I'm quite sure the core Prime Ministerial duties can be fulfilled by a combination of Teams/Zoom meetings, notes under the door, and shouting through closed doorways. And yet, our PM seems mostly invisible. It's just another walk-in fridge, innit.