This column may seem as if it’s just about Labour. But I hope in the end you’ll see that it is also about the Conservatives. It starts with something puzzling.

On Sunday, the Labour shadow cabinet member Barry Gardiner defended Labour’s position that any deal with the EU must secure the same benefits as membership of the single market, despite not being in it.

Mr Gardiner struggled a little during his appearance on the BBC because, as a recording showed, he had once privately (and accurately) described this position as “bollocks”.

The struggle was fun to watch but readily comprehensible. By making an impossible demand, Labour is putting itself in a position where it can vote down any Brexit deal. It’s cunning or disreputable, according