LONDON (AP) — China's ambassador to Britain has warned that U.K.-Chinese relations are at a crossroads following the U.K. government's delaying of a decision on a new nuclear power plant backed by Chinese investment.

In an article for Tuesday's edition of the Financial Times, ambassador Liu Xiaoming made a direct link between the future of relations and the fate of the 18-billion-pound ($23 billion) Hinkley Point project. He described ties as at a "crucial historical juncture" and stressed the importance of "mutual trust" to the two countries' relationship.

Britain's new Prime Minister Theresa May surprised the business world when she stalled the deal last month in order to review the power project in southwestern England, financed by a Chinese nuclear power provider and French energy giant EDF.

The delay threw into doubt the "golden era" of ties proclaimed by Chinese President Xi Jinping during a visit to Britain last year.

The ambassador wrote that he hoped "the U.K. will keep its door open to China." He urged the British government to decide as soon as possible to proceed with Hinkley Point.

Some British politicians and diplomats are wary of the enthusiasm the previous government of Prime Minister David Cameron showed for boosting ties with Beijing.

Britain rolled out the red carpet for Xi during a lavish state visit in October, complete with a stay at Buckingham Palace as the guest of Queen Elizabeth II.

The two countries signed more than 30 billion pounds in trade agreements during the trip, as Cameron said Britain would be China's "partner of choice" in the West.

The visit also saw protests by pro-Tibet and human rights demonstrators concerned about the British government's lavish welcome for the Chinese leader.

And there was later embarrassment when the queen was caught on microphone saying Chinese officials had been "very rude to the ambassador" while the visit was being organized.