You prepare for the programme by being a manic swot. For weeks, you digest as much information as you can: seats, polls, personalities, policies and constitutional options. You commit lots to memory because there’s no time on the night to thumb through lever-arch files. There’s a relentless flow of information through your earpiece: director’s comments, producer’s ‘requests’ (orders, usually), researchers’ messages — they all combine to make the programme happen on the night, backed by an army of staff across the UK. It is, quite simply, the most extensive live outside broadcast undertaken by the BBC. And I’m on screen, at the centre of it all, pinching myself.