Chinese Premier Li Keqiang, left, and Britain's Prime Minister David Cameron attend to oversee the signing of deals ranging from energy, finance and infrastructure to climate change in London on June 17, 2014. [Photo/China News Service]

Britain also welcomes Chinese investment in the Hink-ley Point project, the UK's first nuclear power station for two decades.

Under an agreement, Chinese companies are welcome to take a lead in developing other British nuclear power plants and establishing Chinese nuclear reactors in the UK.

Last year, Cameron welcomed Chinese investment in Britain's infrastructure sector when he led what was reportedly the biggest trade delegation to visit China.

In return, about 200 Chinese business leaders are accompanying Li on his visit to the UK.

On Tuesday, Li called on the two nations to realize a $100 billion annual trade target by the end of 2015, up from $70 billion achieved in 2013.

Britain is China's second-largest trading partner in the European Union and its second-largest source of foreign investment.

British companies landed deals worth more than $25 billion with China.

Oil giant BP signed an agreement worth $18 billion to provide China National Offshore Oil Corp with liquefied natural gas for 20 years, starting in 2018.

Robert Wine, press officer for BP Group, said the company has a relationship with key Chinese energy companies dating to the 1970s. BP is one of the biggest foreign investors in China's energy sector and intends to continue this relationship, he said.

Royal Dutch Shell announced a global alliance with CNOOC on Tuesday to bolster an already strong relationship. It includes three production-sharing contracts in the Yinggehai Basin in the South China Sea.

The energy deal will help boost China's efforts to reduce reliance on coal and to improve air quality.

Zhao Yinan in Beijing contributed to this story.

Contact the writers at xingzhigang@chinadaily.com.cn and zhangchunyan@chinadaily.com.cn.