[harryb]

Interesting thought. If this did happen I wonder what would happen for rolling news of a major event. Would that mean the national presenters cover it on BBC One? Will be a big change if that did happen. Hope it doesn’t.

I would assume it would be done in the same context that ITV do it. The BBC have a strong iPlayer brand that can show live channels and live streams at a touch of a button. Most smart telly’s support iPlayer and will be able to stream to tv any of the live streams. 
ITV1 break away from programming for major events just as BBC One would.