Particular pride of place in my rather eclectic DVD collection falls to a French comedy. Rien à déclarer tells the story of a cantankerous (and French-hating) Belgian customs official and his Gallic counterpart in the run-up to the launch of the Single Market and the removal of customs barriers. It is a journey flick. The anti-hero begins as a character who goes out at night into the fields to move the border markers a few metres southwards. After spending time in a cross-border unit operating from a clapped out (but later souped up and pimped up) Renault 4, they come to get along. I rather think this form of comedy trope – rather than the practicalities of what a custom union is for, the limits to what it can achieve and its concomitant political baggage – is what has driven some political figures of late. The prospect of the UK joining a customs union after Brexit was so preposterous that the Cameron Government itself casually dismissed it as a serious alternative to EU membership. It is an act of superlative cynicism and indeed parody to now find it lifted from the jetsam by establishment peers, and paraded like a revolutionary hostage by their tricoteuse counterparts on the green benches. But for those still on the fence, there are three further aspects to this debate that may also now be worth bearing in mind. The first relates to the mandate. It is plum wrong to pretend that there was no referendum mandate to leave the Customs Union, or indeed as some business figures breezily moot, to leave the EU’s one and to concrete ourselves into a new counterpart. Let’s set to one side the long narrative of the Eurosceptic movement on this, for example the narrow caveat in Change or Go that stated the model was a poor option and “at best forms a secondary transitory route covering a very limited period”. Let’s put to one side the various references in speeches by Leave campaigners during the referendum campaign itself, clear as these were. Let’s go straight to the nearest thing that existed to a “Leave Manifesto”. The evidence, as we at The Red Cell have detailed in a short briefing note, is incontrovertible. On the Vote Leave website – that is to say the website of the officially-designated campaign, prominently set out, from a very early stage, in a section even entitled “What leave looks like”, the campaign stated that “We will take back the power to negotiate our own trade deals”. In fact, this pledge was the second bullet point in the introductory summary list. This cannot be done if you are in a customs union – as M. Barnier himself has helpfully acknowledged this week for the avoidance of any doubt. Secondly, there’s the logic black hole. As we also set out in a separate paper, for starters the precedent is rubbish. The Turkish model clearly does not address the concerns that are driving pro-Customs Union ‘Backtivists’, since the key issues that relate to Technical Barriers to Trade would still have to be covered by separate free trade arrangements. We ought then look at all the other models involving customs unions and enhanced customs arrangements with non-EU states – which all turn out to be with countries and territories with populations smaller than the constituency of the average MP. The third point is the extent to which all this is really a “Birthday Routine”. Tyrese Gibson in Fast and Furious 7 is obliged to cause a distraction at a party, which he does by taking over a DJ’s microphone and trying to start a singalong to celebrate a random guest’s birthday. We might legitimately ask to what extent are many of those involved in this customs gameplay genuinely concerned about the specifics, or also merely trying to distract the guests from a heist that is going on? We’ve thankfully been reminded recently of some of the concerning elements of the transition deal relating to the UK’s fisheries and the enduring risks from the end arrangements – but there are a considerable number of other post-Brexit elements that a pro-active and vigilant parliament should really be focusing on, and which have profound implications for civil liberties and democratic accountability. These include the risk of Whitehall supergluing itself to the European Defence Agency, and the establishment of a single market in defence. They include the peculiar free lunch the Home Office appears to be throwing over Justice and Home Affairs deals, and incorporating the European Arrest Warrant and Europol. They include the barely discussed issue of the depth of UK linkage to 53 EU agencies involving €10bn in budget and 15,000 staff – on which more details can be found here. These are fundamental and wide-ranging questions that Parliament instead should be intelligently perusing, and where the default in the civil service is to lean towards the status quo rather than injecting ambition, reform and good governance. MPs would be wise to challenge former civil servants in the Lords on their silence on these issues, rather than simply joining in their loud birthday songs over a clearly enunciated referendum commitment on trade.