James Frayne is Director of communications agency Public First and author of Meet the People, a guide to moving public opinion. The focus of this column is Theresa May’s conservatism for “ordinary working people”.

By the 2025 election at the latest, campaigning will take on a retro feel as parties sell their policies on international trade. The language of global free trade, tariffs and protection will become part of the political lexicon again. What the parties finally offer will be influenced by where the public is. So what should the parties know about public opinion as they create policy?

There are three key principles affecting opinion. The first is fear – and it regards our relationship with the EU. There is deep public concern that Britain should secure some sort of free trade deal with Europe. A YouGov poll in August 2016 showed that, given a range of options for Britain’s future relationship with the EU, the most popular option was one “based primarily on free trade”. Furthermore, by a massive 79 per cent to 9 per cent, people said that it was important Britain secured a free trade deal with the EU on leaving.

Of course, it isn’t clear what people want a deal to look like. And the fear the Remain campaign fostered about losing access wasn’t enough to win the referendum. But we are where we are: the fear of losing a close trading relationship is strongly felt; it will take a significant communications effort from those that want to leave the customs union to persuade the public of the merits of it. Voting to leave was not a vote to pull up the drawbridge, regardless of what some commentators suggest.

The second key principle is pragmatism. In short, the British public don’t see trading relationships as being built around things like shared values or affection. In September, YouGov asked the public which countries Britain should prioritise trade deals with. Top came the US, followed by the EU, China, Australia, Canada and Japan.

To underline this further, a YouGov poll in October 2015 showed that by 55 per cent to 29 per cent, people have a negative impression of China, but more people said they expected China to our most valuable trading partner in twenty years than any other country – and 43 per cent of the public said they favoured closer trading ties with China than now, compared to just 8 per cent that said they favoured weaker ties.

The third key principle is suspicion. Polls consistently show ambivalence if not hostility to some of the key pillars of the free market. They don’t believe strongly in small government, nor in choice in public services. They usually say they believe the economy to be stacked in favour of the rich and big business. While this doesn’t relate to trade per se, it is relevant because of the way those that promote free trade tend to go about it.

The big question is ultimately whether this suspicion over free markets becomes a more visible feature of our political conversation as people start to consider who the removal of tariffs really benefits. This is, of course, a major part of the debate around free trade elsewhere. But the fear that British people have for a potential loss of prosperity and their current acceptance of the need to trade with whoever is richest means that politicians should currently take a pro-trade, pro-free trade position. Time will tell if this holds.