The next Parliament must replace one-liners with a proper debate on our future relationship with the EU

With yesterday’s vote demonstrating Parliamentary support for the Prime Minister’s new Brexit deal, at least in principle, it seems probable that we are now on track for a negotiated exit from the European Union. Yet even at this hour, MPs are misrepresenting the economic reality of the deal they have been tasked with scrutinising.

It is worth pausing for a moment to reflect on where the debate on the economic implications of Brexit has gone wrong so far to make sure that once the deal is passed, further debates are firmly grounded in reality. One instance, in particular, is worth drawing attention to – and I do so as a post-mortem rather than a name and shame.

Liberal Democrat MP, Chuka Umunna, claimed last week that the Prime Minister’s Brexit deal would lead to a 6.7 per cent drop in GDP and 6.4 per cent fall in real wages; conveniently leaving aside the fact that these figures came from the Government’s forecast analysis of moving to an average Free Trade Agreement with the EU after 15 years, compared with remaining in the EU.

Umunna’s claim is wrong on two accounts. First, even if a Free Trade Agreement similar to that modelled by the Treasury was reached with the EU, there would not necessarily be a “drop” in GDP or real wages according to the analysis. Instead, what the analysis demonstrated was that under a certain set of assumptions, GDP and real wages would be lower by the projected amounts. However, over these 15 years, the economic growth will almost certainly far outplace the projected 6 per cent reduction, with limited evidence that any sudden “drop” would actually materialise.

Second, and more importantly, MPs are only being asked to vote on the terms on which the UK will leave the EU, not the future trading relationship between the pair; which will be discussed in the next phase of the negotiations. So talk of the precise economic implications of the Brexit deal is simply misplaced. Many pieces of the puzzle are yet to be determined and there is a case to be made that once the deal is passed, a General Election could help secure a democratic mandate for what the future relationship, economic and otherwise, ought to look like would be a helpful development.

Umunna later acknowledges the fact that the Prime Minister’s Brexit deal leaves the future relationship to be determined, and he is most likely aware of the inconsistencies in his claim. But herein lies the problem. For too long MPs opposed to any Brexit option – many of whom, Umunna included, voted to trigger Article 50 – have opted for the short-sighted strategies of rubbishing Brexit as economic self-harm. But this has stifled any real debate about the long-term economic consequences of Brexit, on which the eventual future relationship will largely depend.

Let us not forget that the Brexit was fundamentally a political decision. Voters raised concerns about immigration, sovereignty, regulation and the UK playing a more global role. Yet distancing ourselves from the EU will come at an economic price and there is a legitimate debate to be had about the areas in which the UK ought to diverge from and where it is in its interests to remain closely aligned with the EU.

It is also likely that a general election is only around the corner. This will present political parties with an opportunity to put forward a vision for their desired future relationship. It is vital that the next parliament learns from its predecessors’ failings and ceases to misrepresent the realities of each other’s desired Brexit destinations. Instead, they must engage in a serious discussion about the trade-offs of the potential options for the future relationship. Anything less will leave the UK impoverished.