I’ve been trying to work out what bothers me about the response to Jeremy Corbyn’s interview on the Andrew Marr programme.

What bothers me about Corbyn’s interview is obvious: the use of the phrase “wholesale importation” to describe people coming from Eastern Europe to the United Kingdom makes them sound like boxes of sugar rather than people. Adding to that, by suggesting that this “importation” had “destroy[ed] conditions”, rather than laying the blame on Britain’s under-enforced and under-regulated labour market, his words were more appropriate to a politician who believes that immigrants are objects to be scapegoated, not people to be served. (Though perhaps that is appropriate for the leader of the Labour Party if recent history is any guide.)

But I’m bothered, too, by the reaction to another part of his interview, in which the Labour leader said that Britain must leave the single market as it leaves the European Union. The response to this, which is technically correct, has been to attack Corbyn as Liechtenstein, Switzerland, Norway and Iceland are members of the single market but not the European Union.

In my view, leaving the single market will make Britain poorer in the short and long term, will immediately render much of Labour’s 2017 manifesto moot and will, in the long run, be a far bigger victory for right-wing politics than any mere election. Corbyn’s view, that the benefits of freeing a British government from the rules of the single market will outweigh the costs, doesn’t seem very likely to me. So why do I feel so uneasy about the claim that you can be a member of the single market and not the European Union?

I think it’s because the difficult truth is that these countries are, de facto, in the European Union in any meaningful sense. By any estimation, the three pillars of Britain’s “Out” vote were, firstly, control over Britain’s borders, aka the end of the free movement of people, secondly, more money for the public realm aka £350m a week for the NHS, and thirdly control over Britain’s own laws. It’s hard to see how, if the United Kingdom continues to be subject to the free movement of people, continues to pay large sums towards the European Union, and continues to have its laws set elsewhere, we have “honoured the referendum result”.

None of which changes my view that leaving the single market would be a catastrophe for the United Kingdom. But retaining Britain’s single market membership starts with making the argument for single market membership, not hiding behind rhetorical tricks about whether or not single market membership was on the ballot last June, when it quite clearly was.