President of China Xi Jinping (R) and his wife Peng Liyuan (2nd L) accompany Britain's Queen Elizabeth (2nd R) and her husband Prince Philip, The Duke of Edinburgh (L) as they arrive for a state banquet at Buckingham Palace in London, Britain, October 20, 2015. [Photo/Agencies]

British Prime Minister David Cameron described the deal as "historic". The project, in which the Chinese take a one-third stake, will provide reliable and affordable energy to nearly 6 million homes and create more than 25,000 jobs.

"Britain definitely needs to modernize its infrastructure. This is a win-win situation here," Shada Islam, director of policy at Brussels-based think tank Friends of Europe, told Xinhua.

Additionally, the two nations on Thursday issued a joint declaration on building a "global comprehensive strategic partnership for the 21st century".

The document pledged joint efforts in fields ranging from the internationalization of China's yuan and a China-EU free trade agreement to cybersecurity and climate change.

"This is a guideline to tell people how the 'golden era' will be forged," Cui said.

Qu Xing, China's ambassador to Belgium, noted that the visit follows Xi's first European tour as Chinese head of state last year to the Netherlands, France, Germany and Belgium.

This has shown a strong continuity in China's European strategy, Qu said.

Xi has said that since Britain is an important member of the EU, the China-UK relationship and China-EU relationship reinforce each other.

China hopes to see a united European Union in which Britain plays a prominent role in promoting Chinese relations with the bloc, Xi told Cameron during the visit.

Xinhua contributed to this story.

lixiaokun@chinadaily.com.cn