For some, the great prize of Brexit is so called “Global Britain” and the ability to more readily sign new free trade agreements. On Sunday, in his speech at Conservative Party conference, International Trade Secretary Liam Fox celebrated the fact the UK was:

“able to start our public consultations on future new free-trade agreements with the United States, Australia and New Zealand as well as potential membership of CPTPP, the transpacific trade partnership that includes Japan, Canada and Mexico, some of our most important trading partners and a sign that we are committed to a truly global Britain in the future.”

Ignoring whether putting up barriers to trade with our biggest trading partner, the EU, in order to potentially lower them with countries further away is a good idea from an economic perspective (there is no reason to think it is), such a superficial narrative runs the risk of leaving Britain under-prepared for the realities of trade and trade liberalisation. Because, when you delve beneath the bombast you quickly realise that trade and trade disputes are complex, bizarre and at times, well, a little petty.

To give an example, The Guardian recently reported that a hundred boxes of British Weetabix were to be destroyed on the order of a New Zealand judge. They had been held by customs after a New Zealand firm brought a case arguing that the Weetabix name is too similar to its own trademarked product, Weet-Bix, and it could lead to shoppers being confused. This is despite Weetabix only being stocked in speciality stores selling only British products.

If this sounds absurd, that is because it is. But such disputes are not at all uncommon.

One of America’s big issues with the European Union when it comes to trade, as per its annual report on foreign barriers to trade, is the EU’s approach to whisky labelling. For a product to be sold as whisky (or whiskey) in the EU it must have been aged in barrel for over three years. Of particularly annoyance to the US is the fact that other markets such as Russia and Israel have adopted the same approach. The US continues to argue that due to innovative barrels, it can create high quality whisky in under three years, but to no avail.

Perhaps one of my favourite slightly odd examples is that of the US Court of International Trade settling a long-running nerd debate and ruling that the X-Men, mutant superheroes in the Marvel comic book universe, are not human.

This crucial judgement occurred after a company importing X-Men dolls into the US realised that it was being charged a higher import tariff than other toys. In order to qualify for the lower tariff, the company’s lawyers had to demonstrate that the X-Men were not in fact dolls (representative of humans) and were instead toys (representative of a non-human).

For the purposes of re-classifying the X-Men and determining what tariff to levy on these children’s toys, the court was required to consider the “subjective characteristics of mythical or fictitious characters” and in effect draw a line under the X-Men’s claim to humanity.

The judge’s opinion is really quite something to behold.

It acknowledges that most X-Men figures are on the “borderline” of resembling humans “in that they exhibit a mix of human and non-human characteristics”. For example “‘Wolverine’ has long, sharp-looking claws grafted onto his hands that come out from under his skin along with wolf-like hair and ears.”

But, ultimately, the decision rested on whether these additional characteristics "fall far short of transforming [these figures] into something other than the human beings which they represent" and decided the issue “is not a straight headcount of the human features a figure may possess, rather the issue is whether the figure as a whole and in a wider context represents a human being.” Which the judge decided they didn’t.

Deep, I know.

Free trade agreements are great as political window-dressing, and of course can be the means through which some of these issues are addressed – but slightly bizarre, behind-the-border grievances are often what really matter. The grouping of countries that has managed to go furthest when it comes to resolving such issues between its members is the EU, and in practice it required creating supranational enforcement and judicial bodies, a harmonised rule book, and political infrastructure.

A free trading Britain, free of the shackles of Brussels, sounds nice as a rallying cry, but the real world is much more complicated, and if its proponents aren’t careful, they are setting themselves up for a rude awakening.

Sam Lowe is a senior research fellow at the Centre for European Reform, and a visiting research fellow at The Policy Institute, Kings College London. Follow him on Twitter @SamuelMarcLowe