For four years, as Leader of the Opposition, my job was to interrogate Tony Blair every week at Prime Minister’s Questions; a close approximation to trying to nail jelly to a wall.

I used all the techniques ever devised of presenting him with a question demanding a “yes” or “no” answer, where both “yes” and “no” were politically impossible to say. And he employed every means known to a seasoned politician of addressing a question without ever coming down on either side of it.

Even one day when the First Minister of Wales resigned minutes before PMQs – news of which reached me but not him – and I immediately tried to trick him into expressing confidence in that Minister, Blair sniffed the air, smelt the rat, and talked about Wales in general. When it came to obfuscation, he was a class act.

The perfection of this art is the ability to say something that sounds very definite and even dramatic, but which really leaves the listener none the wiser. And while in the Commons this is just sport – my Chief Whip used to say to me each week “Thank God it’s only a game” – it is a little depressing to see so much of the referendum campaign based on this art.