Prime Minister Theresa May is making her debut on the global stage with a series of face-to-face meetings with world leaders at the G20 summit in China.
Mrs May's first top international gathering as PM sees her holding bilateral meetings with US president Barack Obama and Russian leader Vladimir Putin on Sunday.
The Prime Minister hopes to use the summit of the world's most advanced economies to portray the post-Brexit vote UK as a "global leader" for free trade.
Mrs May meets Chinese president Xi Jinping for bilateral talks on Monday, with a question mark still hanging over whether she will give the go-ahead for the £18 billion Hinkley Point nuclear power plant deal between the two countries.
Speaking as she left for the summit in Hangzhou, eastern China, Mrs May said: "The message for the G20 is that Britain is open for business, as a bold, confident, outward-looking country we will be playing a key role on the world stage.
"This is a golden era for UK-China relations and one of the things I will be doing at the G20 is obviously talking to President Xi about how we can develop the strategic partnership that we have between the UK and China.
"But I will also be talking to other world leaders about how we can develop free trade around the world and Britain wants to seize those opportunities. My ambition is that Britain will be a global leader in free trade.
"I will be talking to other world leaders about the opportunities for trade around the globe that will open up for Britain following Brexit.
"I will be talking about how Britain will be seizing those opportunities."
Mrs May is not expected to use the visit to make an announcement on the Hinkley Point project, which is backed by Beijing's state-owned nuclear firm.
The PM has said she will make a final decision on the deal later this month.
The French energy giant EDF, with support from China General Nuclear, had expected to build the plant, but in a surprise move Mrs May's administration signalled a delay in making a final decision on the project amid reports of security concerns about Beijing's involvement and the high cost of energy from the power station.
With the UK seeking a new role on the world stage following the Brexit vote, the decision on Hinkley Point has major diplomatic implications for relations between the UK, France and China.
Mrs May will also have a meeting with her Indian counterpart Narendra Modi, with the trading relationship expected to dominate the agenda.
During the summit, Mrs May will have the chance to mingle with world leaders - including during a boat trip on Hangzhou's lake - for the first time since the EU referendum.
Mrs May is set to use talks with Australian premier Malcolm Turnbull at the summit to shape the broad outline of what could be the UK's first post-Brexit trade deal with the country, according to The Sunday Telegraph.
Mrs May's aides have been warned to avoid "honey trap" encounters with Chinese spies while at the summit, the paper said.
Officials have been issued with temporary mobile phones and internet addresses to try and evade Chinese hackers, and told to get changed under bedclothes if they did not want to be filmed naked in their hotel rooms, according to the report.
Downing Street declined to comment on the claims.