By William James

LONDON (Reuters) - Finance minister George Osborne met senior Chinese officials in London on Thursday to discuss trade following Britain's vote to leave the European Union, agreeing to work to foster stronger ties between the two countries, a source close to Osborne said.

Britain's trading relations with the rest of the world have been thrown into sharp relief by the June 23 vote to leave the EU, through which it has negotiated its trade deals for decades.

Following the meeting between Osborne, Chinese Ambassador Liu Xiaoming and other senior Chinese officials, the source said there had been "productive discussions on investment, financial services, and fostering stronger trading ties" when Britain is outside the EU.

The Brexit vote threatens to redefine Britain's growing financial services relationship with China, which has agreed to a number of joint projects as part of the China-UK Economic and Financial Dialogue program to deepen economic ties between the two countries, based largely on the UK's membership of the EU.

Osborne used the meeting to restate a determination, first expressed by Chinese President Xi Jinping on a state visit to Britain last October, to sustain what both countries have called a "golden era" in bilateral relations.

The meeting formed part of the preparations for a G20 finance ministers' meeting in Chengdu later this month. Osborne will use that trip to visit several cities to promote UK-China relations in light of the referendum result.

Earlier this week he underlined the need to work on Britain's trading relations, saying in a newspaper interview: "We have got to get on a plane and sell Britain to the world."

(Reporting by William James, Editing by Kylie MacLellan)