I USED to work as a speechwriter on Capitol Hill for the distinguished American senator Daniel Patrick Moynihan.

He was a wise old owl. He'd a theory that people voted in presidential elections for folk they'd like to sit down and have a drink with.

It sounds a little trite. But America voted Bush junior over the eminently better qualified Gore and Kerry, Clinton over Bush senior, Reagan over Carter and Mondale, and Biden over Trump.

Likeability does seem to play a key role in one-on-one debates where, over two the course of several hours, voters get to assess the cut of candidates' jibs.

Panels are different. I'm on one tonight – the BBC's 'Debate Night'.

On panels you're one of four or five. So, you've relatively little time to make a positive impression but plenty of time to make a gaffe.

The production team never tell you what the questions are in advance. And you get no help at all from the presenter. As a former broadcaster myself that disappointed me.

On my first 'Question Time' outing, I was hoping for favouritism and got none. David Dimbleby puts his arm around his note of upcoming questions like a primary schoolboy swat refusing to help his delinquent, underprepared friends.

Knowing, perhaps, that sport wasn't my strongest area he questioned me on sport at my first 'Question Time' appearance. Fortunately, I knew he didn't know anything about sport at all and threw the question right back at him.

He got the answer right but only after his producer yelled it into his earpiece, something I heard as I was sitting next to him. Something that I pointed out. Two can play at that game.

When I made the career crossover from journalism to politics, I swore I'd avoid the cliches I most disliked when I heard them as an interviewer.

I promised myself I would never talk about 'hard working families' (as if single people are all lazy wastrels) and I'd never say 'frankly' when I was making a point devoid of any special candour.

I also promised myself that I'd try to avoid blustering. Audiences see through it.

Andrew Neil – an outstanding interviewer with whom I disagree about almost everything – had me as a regular on his evening show 'This Week'.

I once asked his editor why. "Because you say 'I don't know' when you don't know something" she replied. "Andrew loves that as it's so rare."

And of course, it's blindingly obvious you can't know the answer to everything. Who does? So why pretend? The difference between the interviewee and the person asking the questions is that the latter has both the questions and answers written down.

But while it's okay to say "I don't know" on occasion, disarming the interviewer with candour, it's not good to overuse the phrase lest you get a reputation as an underprepared numpty.

No politician in any party wants that, though many have unwittingly earned the epithet.

Time to go back to the swatting.