If it's an 'address the nation' it will be pre-recorded.
There will be crossed Union Flags.
He'll be sat at a desk.
There will be somber words and probably latin. Maybe greek. Almost certainly a cry to the braveries of our past. "When Harold had the arrow in his eye, did he despair? No, he did not despair. Did he give up? No. No, he did not..."
He will be Churchillian. Badly.
He probably will have brushed his hair, which is at least a small mercy.
I have wine in the fridge. I think I might open it.