May will use meetings with President Xi Jinping and Premier Li Keqiang to try to regain momentum in the international race to secure British participation in China's services sector boom as she seeks a new role for Britain outside the European Union.

Travelling with her husband Philip and a delegation of 50 business leaders, May has to reheat diplomatic ties that have suffered from a perceived coldness since she took power shortly after Britain's Brexit vote in July 2016.

“My visit will intensify the 'Golden Era' in UK-China relations. The depth of our relationship means we can have frank discussions on all issues," May said in a statement. She is due to depart on Tuesday afternoon.

May has echoed calls by U.S. President Donald Trump for China to press neighbouring North Korea into reining in its nuclear and missile development.

Britain has also previously expressed concern about steel overproduction, human rights abuses and the health of democracy in former British colony Hong Kong.

The Guardian reported that Britain's last governor in Hong Kong before it was handed back to the Chinese, Chris Patten, had written to May urging her to raise the erosion of rights and freedom in the territory.

In the past sensitive diplomatic issues have spilled over into trade talks, with May's predecessor David Cameron prompting a freeze in relations in 2012 by meeting the Dalai Lama in London.

With Britain about to undergo its most significant economic upheaval since World War Two, relations with China are set to become increasingly important as May's government looks to develop markets outside the EU.

But Chinese officials have expressed unease about what Brexit could mean for Chinese firms who have invested in Britain.

May is also under pressure to deliver a positive story in China from those closer to home. Her position as leader has been weakened by ministers openly lobbying for different types of exit and hardline eurosceptics unhappy at her Brexit strategy.

Trade secretary Liam Fox will head a diverse delegation ranging from executives of large multinationals like HSBC (>> HSBC Holdings) and AstraZeneca (>> AstraZeneca) to smaller firms like Northern Irish seafood wholesaler Rooney Fish.

"Our relationship is now more important than ever, as we look to form new trading bonds with the biggest growing markets around the world," Fox said, citing data showing China's middle class is expected to grow to 600 million people by 2020.

(Reporting by William James; editing by Ralph Boulton)

By William James

Stocks treated in this article : AstraZeneca, HSBC Holdings