British Prime Minister Theresa May is visiting Japan this week in a bid to boost investment in the wake of Brexit. Japanese officials are, however, already warning her not to expect too much.

Mrs. May has met Japan's Prime Minister Shinzo Abe twice since she took over in Downing Street but this will be her first visit to Japan as the country's leader.

​It is an opportunity for her to press home the "Britain is still open for business" message she has emphasized since the Brexit vote.

Several Japanese companies have sizeable investments in Britain, including Nissan's huge car factory in Sunderland, Toyota's auto plant in Derby and Nippon Sheet Glass, which owns the Pilkington glassworks in St. Helens.

But from March 2019, Britain will be outside the EU and Mrs. May is expected to offer trade incentives to Japanese companies in the hope they will not switch investment away from the UK.

Mrs. May arrives in Tokyo on Wednesday, August 30, and will also have a meeting with the ailing Emperor Akihito, who is expected to abdicate soon in favor of his son, Crown Prince Naruhito.

Watch David Davis as he arrived in Brussels today and reiterated his call for a deal that works in the best interests of the UK and the EU pic.twitter.com/j5KRduBLfc — Exiting the EU Dept (@DExEUgov) 28 August 2017

​Downing Street said Mrs. May would be accompanied by "a delegation of business leaders drawn from a range of sectors."

"The delegation will showcase the strength of British business, the shared confidence in the UK-Japan economic relationship as we leave the EU, and the potential for future growth," said Downing Street.

But Japanese officials have told the Financial Times their priority was negotiating a deal with the European Union, which represents a far larger market than the UK.

One official said they felt Britain was being "quite aggressive" in trying to hammer out an Anglo-Japanese trade deal and said they did not think there would be "substantial progress."

Mrs. May hosted Mr. Abe at the prime minister's country residence, Chequers, in April and also met him at the G20 in Hamburg in July.

"Her visit is expected to cover a wide range of bilateral and regional issues, including working together to support the rules-based international system and the promotion of free trade and democratic values," said Downing Street.

Her meeting comes as Japan recovers from the shock of a North Korean ballistic missile flying across the country on Tuesday morning, August 29, before breaking into three pieces and falling into the sea 733 miles from Cape Erimo in northern Japan.