Let’s be clear.  Britain could both remain in the Single Market and leave the EU.  This is more or less the position that the EFTA countries are in – Norway, Iceland, Lichtenstein and Iceland.  All are Single Market members.  None are EU member states.  Ken Clarke, Nicky Morgan, Dominic Grieve, Anna Soubry and those Conservatives who, when push comes to shove, want to stay in the Single Market are therefore not seeking to keep Britain in the EU by doing so.  They are not guilty of any such charge.

However, what Britain could not do is stay in the Single Market and control immigration from the EU effectively.  Reference has been made to Lichtenstein’s emergency brake.  But it is not certain that Britain could join the EEA in the first place (even if the Government wished to, which is apparently not the case), and very clear that an emergency brake is no substitute for proper controls.  Ministers are plainly moving towards a work permit system, as outlined on this site recently by Andrew Green.  It represents a better way forward.

What Clarke et al are therefore saying is that the Goverment should drop any real attempt to control immigration post-Brexit.  They are scarcely alone in pretending that the circle of single market membership and proper immigration control can be squared: both Government and Opposition are playing the same game, though David Davis’s heart isn’t really in it.  But this is not a position that would honour the referendum result.  Reducing immigration was not the main reason for the Brexit vote, but it was an important one, as Lord Ashcroft’s and other research has shown.

But although Clarke and company are right to say that by championing single market membership they are not thereby calling for Britain to remain in the EU, they are wrong to claim that the Conservative Manifesto gives them a mandate for pursuing continued membership.  The manifesto’s actual words were: “we say yes to the Single Market”, which is not quite the same thing.  However, even if it can be read to be so that is not the end of the matter.  For the manifesto also repeats the commitment to aim to deliver “annual net migration in the tens of thousands”.

The last is only deliverable if that first is not delivered at all.  And the referendum result has given the Government a popular mandate to prioritise reduced migration numbers over single market membership.  That referendum was of course itself also a product of a promise in the very same manifesto.   It is surprising that Morgan and company, who are intelligent people, have not grasped this yet.  They may be comforted by the fact that even if Britain is not to be a Single Market member post-Brexit it will continue to have Single Market access.

Yesterday’s setting for this shadow-boxing was the Commons.  More nonsense has been talked about its Brexit role, both inside and outside the chamber itself, than this site could possibly do justice to.  It is arguable that Parliament itself should vote on triggering Article 50, and arguable too that it should vote on any eventual deal – though, rememeber, that if it rejects any deal it will be left with nothing, since Britain will exit the EU automatically two years after the Article is moved (unless all parties concerned agree to an extension of the talks).

However, Parliament cannot practicably either demand to see the Government’s detailed position before negotiations begin nor rewrite that position itself.  It will be countered that Parliament is sovereign, and can do whatever it likes.  This is technically true but, in this context, almost meaningless.  To grasp the point, consider what would happen were the Commons to vote through a motion demanding that the Government pursue membership of the Single Market at the expense of migration control.

The Government would doubtless, first, pay due lip-service to taking MPs’ views on board and then, second, ignore the vote completely (in effect).  It is a constitutional misunderstanding to claim that such a vote would have been “binding” – to use the word that is often bandied about in these circumstances.  The Commons passes all sorts of motions making all sorts of declarations.  The Government then decides what to do about them.  These motions are not “binding” – let alone in the sense that measures passed in a Bill bind governments once it has become an Act.

To be sure, the Commons can in the last resort pass a vote of no confidence in the Government if its wishes are ignored.  And it can make the Government’s life very difficult in the interim, which it will doubtless do over the Brexit talks (and, up to a point, should: that’s its role).  But Anna Soubry and company are not going to pass a vote of no confidence in their own government – not, that is, if they wished to be Conservative candidates in the general election that would follow as a consequence.

You may disagree with this view of Parliament’s function and the negotiation’s conduct for whatever reason you can dredge up.  But please note that the Commons does not.  Labour’s motion before it yesterday said that that “there should be a full and transparent debate on the Government’s plan for leaving the EU; and [called] on the Prime Minister to ensure that this House is able properly to scrutinise that plan for leaving the EU before Article 50 is invoked”.  When push came to shove, Labour didn’t press the matter to a vote.

This was presumably because the terms of the motion have already been met.  As Davis explained, the Government has set out its aims: “bringing back control of our laws to Parliament; bringing back control of decisions over immigration to the UK; maintaining the strong security co-operation we have with the EU; and establishing the freest possible market in goods and services with the EU and the rest of the world”.  To demand more now is effectively to demand that the Government set out its negotiating plans in detail – which it shouldn’t do, for obvious reasons.

In short, the Commons is entitled to hold Ministers to account for their conduct of the coming negotiations – and should do so vigorously.  MPs should call for statements, table urgent questions, hold debates, pass motions (if necessary), and generally give the Executive a hard time: that’s what they’re there to do.  What it is neither practical nor desirable for them to do is to seek either to write the Government’s negotiating strategy line-by-line nor to ask for it to be announced to the Commons – and therefore also to the EU institutions – in detail before the talks begin.

Labour accepted this yesterday in principle.  It isn’t always doing so in practice.  As Davis pointed out, some of Keir Starmer’s famous 170 written questions about the Government’s negotiating plan require in effect for it to be revealed in detail in advance.  In short, there is a push on to stay in the Single Market and thus abandon EU immigration control – thereby putting two fingers up to the British people, and the referendum decision they delivered last June.  And all done under a bogus cloak of constitutional propriety.  MPs should have none of it.