The memorandum of understanding was signed in Tokyo on Thursday by Hiroshige Seko, the Japanese trade and industry minister, and Greg Clark, the business and energy secretary.

The agreement is the first of its kind for Japan, while Mr Clark described it as "vital" to the UK's industrial strategy and the development of clean energy sources.

One of the key components of the agreement is the proposals by Hitachi and Toshiba to build new reactors in Britain.

Horizon Nuclear Power, bought by Hitachi from a German company in 2012, has delivered the outline of a project at Wylfa Newydd in Wales, and has plans to build as many as six reactors in the UK. Toshiba joint venture NuGeneration is planning a nuclear plant in Cumbria and is considering additional projects.