Free trade versus protection is one of the oldest stories in modern British politics, and from Sir Robert Peel and the Corn Laws to Joseph Chamberlain and ‘Imperial Preference’, it has often divided the right.

Now Michael Gove and Liam Fox look like squaring up for another (hopefully much more low-key) round of the struggle, this time over the future of British agriculture after we leave the European Union and, in particular, US imports.

Gove, as Environment Secretary, has been laying out his vision for a ‘green Brexit’ in which Britain maintains and enhances its environmental regulations and product standards. Fox, by dint of his position as International Trade Secretary, has different priorities. He wants to strike deals, open up British markets, and remove barriers to trade.

The dispute between the departments could be boiled down to one, simple question: should we allow chlorine-washed American chicken into Britain, or not?

A chlorinated roast has replaced the over-laden, beggar-thy-neighbour German shop as the anti-free trade trope of the moment. Such is the hysteria surrounding American chicken that journalists have ‘dared’ the Trade Secretary to eat one.

On one level, the free trader response to this squeamishness is simple enough: let people choose. It’s already faintly ridiculous to treat food consumed by hundreds of millions of Americans – not to mention British tourists – as ‘poison’. Simply make sure that chlorinated chicken (which is 20 per cent cheaper than the alternative) is clearly labelled as such and let the consumer decide.

With the Department for International Trade keen to lock in Donald Trump’s renewed enthusiasm for a deal, an open-minded attitude towards US regulation would doubtless be a great help.

But things get more complicated when you consider our ongoing trading relations with the EU, which most certainly does not take a “let the consumer decide” attitude where it can instead impose European ideals by regulation. Given Brussels’ deeply-ingrained preference for harmonisation over mutual recognition, any easing of British regulations to bring in global produce may lead to a trickier trading relationship with the EU.

This is a particularly acute problem when it comes to Ireland, which not only has an ideological desire to ensure that the UK-Irish border is as seamless as possible but the practical need to protect its own easy access to the British market, which takes a substantial portion of Irish agricultural exports.

Such disputes are not confined to Brexit: they fit into a much broader battle between those who prioritise human plenty and embrace low tariffs and genetic modification to secure cheap food, and those who prefer to defend the purity of agricultural produce at the price of making it more expensive.

They also intersect with the parallel debate about the future of farm subsidies post-Brexit. Michael Gove has already set out how farmers will need to ‘earn’ subsidies by fulfilling environmental criteria once we leave the EU – but is he also prepared to reach further into his pocket to support British farmers once free trade brings down food prices?

Cheap food from the US and the developing world could be a real shock to the system for British agriculture. DEFRA need to set out how they plan to deal with it, whether that be by pushing to maintain tariff barriers on agriculture, subsidising farmers even further, or facilitating a structural shift in our agricultural sector towards New Zealand’s efficiency-first, minimal-support model.

It’s hard to imagine a Brexiteer like Gove choosing to replicate the Common Agricultural Policy’s protectionist ethos in Britain’s post-Brexit settlement. But if the Government wants British farmers prepared for the risks – and opportunities – of greater exposure to global markets, he and Fox need to start working together.