Simon says Labour should stop faffing around and declare support for the UK staying in the Customs Union. I'd like to amplify and caveat this.

First the amplification. Labour is missing a trick here. It should be linking its policy on Brexit to its wider critique of British capitalism.

It should be pointing out the raw fact that Germany exports much more to countries outside the EU than the UK: half as much again (per person) to the US; 2.5 times as much to Japan; almost four times as much to China; and so on.

This tells us that it is not membership of the Customs Union that is stopping us from exporting more. Instead, the obstacles lie in the short-comings of British capitalism: poor management; lack of entrepreneurial spirits; insufficiently skilled workers; lack of investment; credit constraints; financialization; a lack of price competitiveness; and so on.

Labour should be highlighting these, and its policy responses to them. It should be saying:

Rather than wasting time on free trade deals, we should stay in the Customs Unions and focus on fixing Britain's real economic problems, not the imaginary ones that exist in Brexiters' fantasies. Only by doing so can we make the UK the truly outward-looking global trading nation that Boris Johnson claims to want.

That said, here's the caveat: Labour's vagueness on Brexit is much more forgivable than the Tories'.

What I mean is that there some Labour issues and some Tory issues. Tories, for example, have traditionally been more interested than Labour on defence, as there tend to be fewer military minds on the left (which reflects no credit on the left). But Labour has been stronger on health and welfare policy, for example.

Brexit, however, is almost entirely a Tory policy. I don't just mean that Brexiters tend to be on the right. I mean that it has for years been a much more salient issue for them than it has for the left. For some it has been one of their top priorities for years. Most of the Labour party (with some exceptions!) by contrast made their peace with the EU in the 1980s and didn't give it much more thought. I, for example, had barely considered the UK's role in Europe until a few months before the referendum. I suspect that even most Lexiters have regarded Brexit as a bit like many lefties regard republicanism; if the issue arises, they support it, but they have higher priorities.

Labour's ambivalence about Brexit is, therefore, understandable. It has pretty much no tradition of even thinking about the subject. For some Tories, however, Brexit has been their desire for 30 years. One would expect them, therefore, to have somewhat more than the vague hint of a slight clue about what it entails.

So yes, by all means criticize Labour's vagueness. But remember, Brexit is above all a Tory mess. It's their shit; they should shovel it.