In an apparent bid to play down talk of a speedy agreement with Washington, the prime minister said there were “considerable barriers” to UK firms, ranging from car tariffs to shower trays and pork pies.
The pair are due to meet at the G7 summit in France on Sunday, with the prospect of a trade deal high on the agenda.
As he arrived at the summit, Johnson defended his friendship with Trump, telling HuffPost UK that the President was “popular with large numbers of people in our country”.
Trump has repeatedly referred to his hopes of a ‘phenomenal’ deal with Britain, predicting exchange of goods and services between the two countries could triple in size.
Johnson has also made getting a ‘fantastic’ US deal a priority of his premiership, not least as he may have to rely on fresh sources of trade if there is a no-deal exit of the UK from the EU.
Trump came under fire this summer when he suggested the NHS could be ‘on the table’ in any talks and campaigners have warned about Britain being flooded with chlorinated chicken and hormone-treated beef.
But the PM has now signalled the big obstacles to any deal include not just the need to protect the NHS and farmers but also a string of bureaucratic restrictions on British goods.
With his strongest criticism yet of American plans to slap tariffs on China, he said he was ‘very concerned’ about a trade war and its possible impact on billions of pounds of British exports on goods like whisky.
Speaking as he arrived at the gathering of world leaders, Johnson also declared that “we must do something” to tax American tech giants, even though Washington has suggested it could be a deal-breaker.
However, ahead of his breakfast meeting with Trump, Johnson was careful to praise the president personally. He suggested that Trump was more popular in the UK than widely assumed, adding that “large numbers” of Brits liked his tweets and speeches.
Referring to the trade deal hopes, he said: “I think there is a massive opportunity for Britain but we must understand that it is not all going to be plain sailing.
“There remain very considerable barriers in the US to British businesses which are not widely understood.”