The Japanese prime minister, Shinzo Abe, has promised Theresa May his country will remain committed to the UK after Brexit, but said businesses need “transparency and predictability” during the process of leaving the EU.

A similar warning was delivered to May by the head of the British carmaker Aston Martin, who was also attending the Tokyo trade event at which Abe spoke, as part of a UK business delegation travelling with the prime minister.



Andy Palmer said some companies would inevitably be delaying investment decisions while awaiting details on what a Brexit deal would mean for tariffs and other trade barriers.



“There will be a natural sense of uncertainty for a while. What we all hope is that while is not very long,” he told reporters after Abe and May spoke at the event in Tokyo.

“The sooner we can get to a position where at least, for example, there will be no tariffs, that will be a big breakthrough, because that would allow you to invest with confidence.”

Abe pointedly failed to promise that Japan would pursue a swift post-Brexit trade deal with the UK, one of May’s hopes for her visit.

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On the second day of her three-day trip to Japan, focused on inspiring business confidence in the UK once it is outside the EU, May said she had been cheered by the decision of Japanese companies such as Nissan to invest in Britain after the Brexit vote.

“We will also seek to ensure the freest and most frictionless trade possible between the UK and the EU, and this includes the imperative of a smooth and orderly transition for people and businesses, in the UK and in Japan,” she said.

Abe had warm words for May, saying: “I have trust in the UK economy after Brexit. Even after Brexit, the UK will continue to be an attractive and compelling place for businesspeople, I am convinced of that.”

But he emphasised the importance for businesses of clarity over the departure process. “From the UK, there has to be transparency and predictability in the EU exit negotiations to minimise any damage to businesses. We have received that commitment and we value it greatly,” Abe said.

Palmer, part of a 25-member business delegation travelling with May, said the words of confidence from Japan were heartening, but echoed Abe’s call for transparency.

“In my world, when you decide to design a new car, it takes four years, and will probably cost you a billion dollars,” he said.

“Those are big bets you have to put down and if you don’t know what your sales environment, or your manufacturing environment, is going to be like in four years, you can either hesitate to make the investment or you can make the investment with a certain degree of risk.

“So the more we can hear from the politicians in terms of what they think they’re going to negotiate, or what they are negotiating, where they’re being successful, where there are gaps, the quicker we can get to that, the more predictable we can make our investments.”

Palmer said Aston Martin was committed to the UK, but added: “I can imagine that being more difficult if you’re sitting in Tokyo, Yokohama or Nagoya, or Germany somewhere.”

And he said for all the focus on possible tariffs, it was the prospect of potential non-tariff barriers that “keep me awake at night”.

“What I can’t cope with is my cars being stuck at a French port for six months. That’s far more damaging for business,” Palmer said.

May, who began her trip by announcing that she hoped to fight another election as prime minister, dismissing reports that she planned to step down in 2019 after losing her majority in the June general election, is also focusing on defence issues in Japan.

Earlier on Thursday, the prime minister toured Japan’s flagship aircraft carrier, JS Izumo, on which British military personnel are sharing mine clearance expertise. North Korea, which on Tuesday fired a missile over northern Japan, is known to possess big stocks of mines that could target Japanese shipping lanes.

May said: “We have a long history of cooperation and my visit today is a sign of the growing cooperation and partnership that we have on defence matters.”