Here are a few of the things Mr Paterson told James Forsyth:

“If there was a major fundamental change in our relationship, emerging from the creation of a new bloc which would be effectively a new country from which we were excluded, then I think inevitably there would be huge pressure for a referendum.”

And asked the killer question, whether a referendum would be required, he replied thus:

“I think there will have to be one, yes, because I think the pressure would build up. This isn’t going to happen immediately because these negotiations are going to take some months. But I think down the road that is inevitable.”