Although politicians and pundits have learnt the hard way not to take polls as gospel, the latest Opinium/Independent poll on free trade ought to give the government some cause for alarm. New polling has found that when asked whether ditching current food standards would be a price worth paying for a deal, 82 per cent of those surveyed said keeping current regulations in place should take priority – even if that meant no deal. Meanwhile, just 8 per cent said a free trade agreement with the US should take priority.

Of course this is just one poll and the stark findings could in part be down to the phrasing of the question. But regardless, it touches on what the next big Brexit debate will be: the battle between the protectionists and the free marketeers. As I said in the i paper on Wednesday, there's a common misconception that if the Brexiteers succeed in getting Theresa May to agree to a trade agreement with the EU that sees the UK out of the customs union and able to strike its own trade deals then the battle for Brexit will have been won. However, in truth, it will only just be beginning. Each free trade deal must be ratified by Parliament, so will need to command the support of a majority of MPs.

The problem for the government is there are a large number of MPs – and voters more generally – who back British interests over global competition. This was recently highlighted by the row over blue passports and whether they should be made in the UK even if it costs the taxpayer more money as a result. After a Franco-Dutch supplier (rather than the existing Gateshead-based manufacturer) won the initial contract, a legal challenge was launched, the Daily Mail started a petition, Priti Patel branded the decision a 'national humiliation' and Keir Starmer, the shadow Brexit Secretary, intervened to say they should be made here. Will this group really say yes to a trade deal that could threaten UK farmers’ livelihoods?

One of the biggest achievements of the Leave side in the referendum campaign was that they managed to put on a unified front, even though each Brexiteer has a slightly different view of what Brexit ought to look like. The most fundamental difference relates to free trade – and it means there are two very different outlooks on what Britain should be come March 2019.

Cabinet ministers like Boris Johnson and Michael Gove fall into the pro-free trade camp while MPs like Peter Bone and some Labour politicians are protectionists – who see the Brexit vote as being driven by a desire to curb immigration and protecting British interests. Even if the blue passport row resolves itself, these two tribes are unlikely to make peace anytime soon. This is a problem. For the government’s vision of Brexit to be a success, it needs to be able to pass competitive free trade deals.

But – as the latest survey highlights - the contents of these may well be a turn-off to some voters. Each week there is a new scare story about what various countries want from Britain, from the row over chlorinated chicken coming over from the US to suggestions Australia is preparing to demand that Britain accepts hormone-treated beef as the price of a symbolic early Brexit trade deal. If they do that, it will be a hard sell both to voters and the agriculture industry. The difficultly is that with free trade, it’s often very easy to work out who the big loser is when the winner is more subtle. Shoppers may have the choice of a slightly cheaper weekly shop but for certain beef farmers the move could end their livelihood.

One theory doing the rounds in government is that hormone-treated beef could be palatable so long as it was clearly labelled as so – that way British farmers could rebrand themselves as the high-quality top of the market option. But if the government is unable to successfully defend a decision to save taxpayers millions by using a foreign contractor, what chance do they have of selling a trade deal that undercuts UK industry?

This is why the government must start making the argument for the type of Brexit – and trading nation – that it wants to be. Even if the Brexiteers do get the free Brexit deal they want, it won’t be worth the paper it’s written on if they can’t get the subsequent trade deals through parliament.