Japan's prime minister has urged Theresa May to set out more details about her Brexit plans after the country gave dire warnings about how leaving the EU could hurt its investment in the UK.

Shinzo Abe called for more "predictability" about the process after the leaders met for brief talks on the sidelines of the G20 summit in China.

Mr Abe told the Prime Minister that he attached "extreme importance" the relationship with the UK and reminded her of the level of Japanese investment in Britain.

But Mrs May said that her talks with Japan and other countries showed they were "confident" about the UK's future.

She pointed to the £24bn takeover of tech firm ARM Holdings by Japan's Softbank as "the single biggest vote of confidence in the UK in terms of inward investment since the referendum".


It comes after Japan issued a 15-page dossier warning of a series of corporate exits and "great turmoil" if Brexit leads to the loss of single market privileges.

Brexit Warning As Leaders Arrive For G20

The dossier made clear that big Japanese firms had invested in the UK because they saw it as a "gateway to Europe".

It warned that they may choose to move their European headquarters to the continent if EU laws stop being applicable in the UK after its withdrawal.

Half of Japanese investment in the EU comes to the UK - including companies such as Nissan, Honda, Mitsubishi and Nomura.

The report warned about Brexit adding to trade tariffs and ending freedom of movement.

There were also concerns about Japanese banks with European headquarters in London losing out on so-called "passport" arrangements enabling them to operate across the EU.

Another worry focused on the potential for London to lose its appeal for pharmaceutical companies, should the European Medicines Agency - currently based in the capital - move to the continent.