Serious damage has been done to the UK's relationship with China and investment could suffer following the government's decision to dump Huawei, Beijing's man in London has said.

Ambassador Liu Xiaoming told a webinar on Wednesday that Britain risks looking like the "junior partner of the United States" after President Donald Trump claimed credit for the U-turn just six months after the UK said Huawei could play a role in its 5G networks.

The diplomat - who has gained prominence over the past year for conveying the views of China's ruling Communist Party in fluent English to a Western audience - also gave his strongest signal yet that a "golden era" between London and Beijing was losing its shine.

Asked what the consequences would be of the Huawei decision on bilateral ties, Ambassador Liu said: "I think it undermines trust in terms of the two countries... I would even say it is not only disappointing, it is disheartening."

He listed Huawei's record over the past two decades as an increasingly important player in the UK telecommunications industry, creating 28,000 jobs and investing more than £2bn.

"The way you treat Huawei will be followed very closely by other Chinese businesses," the ambassador said.

"The mutual trust was undermined and it will be difficult for businesses to have confidence to invest.

"You don't need your government to say anything - the businesses can make their own conclusions.

"So I think the trust is seriously damaged between the government-level and among the businesses."

The webinar was organised by the Official Monetary and Financial Institutions Forum, an economic think tank, and the Centre for European Reform, to explore China-Europe relations.

But a number of questions focused on the UK and Huawei.

The ambassador was asked whether what former prime minister David Cameron declared in 2015 as the start of a "golden era" in UK-China relations was over or tarnished because of the Huawei row and other disagreements - including over Hong Kong.

Ambassador Liu said: "We work together to build this golden era. This is the fifth year of this golden era. I thought we can celebrate the anniversary of the golden era but so many things happen. It is not because of China."

He said Beijing wanted a good relationship with the UK, but blamed what he described as "China hawks and China bashers" for forcing Boris Johnson's government to change path on Huawei.

He also signalled that the UK risked being seen as a puppet of the US.

"I would argue that Britain can only be Great Britain when you have an independent foreign policy rather than to be viewed in China or the rest of the world that you are just a junior partner of the United States," Ambassador Liu said.

"Look at what happened to Huawei: Trump personally pinpointed Huawei, he made a great success.

"Everybody understands what the reason [was] behind the UK decision.

"Whether the UK would want to build a global Britain to exert a global influence, really they have to think deep[ly] [about] what kind of role they are going to play and what kind of position they are going to take."