Theresa May has written to China's president Xi Jinping to reassure him of Britain's continuing commitment to strong relations with Beijing.
The Prime Minister's letter was handed over by Foreign Office Minister Alok Sharma to his Chinese counterpart during an official visit to the Chinese capital.
The move comes after China expressed dismay at a decision by Mrs May to put the development of the Hinkley Point C nuclear power station on hold amid reported concerns about the role of Beijing in the project.
The text of the letter, which was described as "private correspondence", has not been released by Downing Street.
A No 10 source said: "It is about reassuring the Chinese of our commitment to Anglo-Chinese relations."
Earlier this month, China's ambassador to London, Liu Xiaoming, voiced concern at the delay to the £18 billion Hinkley Point project, warning that relations between the two countries were at a "crucial historical juncture".
The surprise decision by Mrs May, just three weeks after taking office, to review the project to build the Somerset power station was widely seen as reflecting concerns about allowing China to invest in Britain's critical national infrastructure.
The Prime Minister's chief of staff, Nick Timothy, had previously written about the possibility that China could covertly install software which would allow it to close down the power station at will.
There was speculation that Mrs May would take a markedly different approach to relations with Beijing from David Cameron and former chancellor George Osborne, who sought to encourage Chinese investment in the UK.
However, in her letter to Mr Xi and Prime Minister Li Keqiang, Mrs May said Britain "looks forward to strengthening co-operation with China on trade and business and on global issues".
On his Twitter feed, Mr Sharma said he had had a "great first meeting" with Foreign Minister Wang Yi, with a "warm welcome and forward-looking approach".