BEIJING - Chinese President Xi Jinping told British Prime Minister Theresa May on Thursday that their countries should take trade ties to "a new level" as London scouts the globe for fresh partnerships after its contentious EU exit.

Hounded by Brexit rows at home, May is seeking to deepen trade relations with the world's second largest economy as Britain prepares to leave the European Union next year.

The embattled prime minister and senior Chinese leaders championed a "golden era" of relations between their two countries throughout her visit.

But criticism in London over her domestic agenda and her handling of Britain's vexed divorce with the European Union loomed large, prompting her to declare she was "not a quitter" before her arrival on Wednesday.

"As the United Kingdom is leaving the European Union we're going to be more outward looking and looking to enhance our relationships around the world, and this relationship with China is an important part of that," May told state broadcaster CCTV.

May held talks with Xi at the Diaoyutai State Guest House tea after visiting an agricultural sciences academy, later taking part in a traditional tea ceremony with the Chinese leader and his wife Peng Liyuan.

The BBC reported that May, who was expected to raise environmental concerns, would present Xi with a box set of the network's Blue Planet II series, with a personal message from presenter David Attenborough.

"We must strengthen the pragmatism of Sino-British relations in the golden era, and push economic and trade cooperation between the two countries to a new level," Xi said during their meeting, according CCTV.

Xi said the two countries can "develop mutually beneficial cooperation on a wider scale, at a higher level and on a deeper level" though his cherished One Belt One Road initiative.

The massive infrastructure programme is aimed at reviving ancient Silk Road trade routes by building rail and maritime networks across the world.

But the project has spurred both interest and anxiety in many countries, with some saying it mainly benefits Chinese state-run firm and has whiffs of expansionism.

May had said on Wednesday that London welcomes the initiative but she cautioned that the two countries would continue to work together to ensure that the endeavour "meets international standards".

Despite the concerns, Standard Chartered announced Thursday a memorandum of understanding in which the British bank would receive 10 billion yuan ($1.6 billion) from the state-owned China Development Bank to back Silk Road projects.

May said the two countries would sign nine billion pounds ($12.7 billion) in business deals during her visit.

The two countries agreed new measures to improve access to the huge Chinese market and set up a special panel to explore trade opportunities, she said Wednesday.

Britain runs a 25.4-billion-pound trade deficit with the Asian giant and only 3.1 percent of British exports go to the country, according to Rajiv Biswas, Asia-Pacific chief economist at IHS Markit.

Brexit crept into her talks with Premier Li Keqiang on Wednesday, though her Chinese counterpart reassured her that their "golden era" of relations would not be affected by London's EU departure.

"As a trade and strategic partner of both Britain and the EU, China certainly hopes that the result (of Brexit) will be good for both sides," said Cui Hongjian, director of the European studies department at the China Institute of International Studies.

"If it comes to a double-lose result, that will be also unfavourable to China," Cui told AFP.

China worries that Britain's EU exit will remove a pro-free trade force from the bloc and give rise to protectionism, he said.

The British prime minister was also under pressure to address the political situation in Hong Kong and human rights abuses in mainland China.

Chinese authorities have carried out a relentless crackdown on civil society since Xi took office in 2012.

But she had yet to make public statements about either matter during her visit, which ends in the business hub of Shanghai on Friday.

Before her trip the former British governor of Hong Kong, Chris Patten, sent a letter to Downing Street saying the semi-autonomous city, which London handed back to Beijing in 1997, was facing "increasing threats to the basic freedoms, human rights and autonomy".