British police failed to protect Chinese diplomatic staff from physical attacks during a violent protest at the country's consulate general in Manchester, Chinese officials have said.

Two members of the consular team suffered injuries, including one who lost consciousness, after an altercation with demonstrators on Oct 16. At least one of the protesters was also hurt.

"The incident on the 16th of October is nothing about peaceful demonstrations or freedom of speech, but all about violent harassment by Hong Kong independence advocates and their illegal assault on the premises and members of the Chinese consulate. It is of a very malicious nature," said Yang Xiaoguang, charge d'affaires at the Chinese embassy in an online media briefing.

A series of security camera video clips aired on the call appeared to show at least two incidents where men identified by Chinese officials as consular staff are knocked to the ground outside the gates.

The staff, some wearing protective clothing, had been removing "provocative and vile" banners displayed outside the compound which contained "life threatening" messages and insults against China and its leaders, said Zheng Xiyuan, China's consul general in Manchester. Requests to the protesters to remove the material had been rejected and diplomats felt forced to act to do their duty in protecting the dignity of their country, he added.

Zheng said that he and his colleagues fully respected the right to freedom of speech and noted that many previous protests had taken place around the location without incident. However, the demonstrators who turned up last week on what was the first day of the high profile Communist Party Congress in China were deliberately provocative and looking to spark an incident, he said.

'Political pressure'

Police say they are looking into what happened, however UK foreign minister James Cleverley has said the Chinese behavior was "unacceptable", raising concerns that the investigation could be subject to political pressure.

"We urge the British side to solve this issue according to the merits of this issue and not to make wrong decisions under political pressure from a few people. We also request the British side provide enough protection for the Chinese missions in the UK in the future," Yang said.

Responding to questions from journalists about demands from some British politicians that Chinese staff should be thrown out of the country, Consul General Zheng pointed out that he had been working to develop ties with the UK in his role for 1,550 days and the latest event was only a "small foam or wave on the vast ocean" of UK-China relations. An "unpleasant" altercation between himself and another protester, shown in videos circulating online, had lasted only just over one minute, he noted.

Another member of staff who was hurt, Consul Gao Lianjia described how he was floored by a man who burst into the grounds of the compound and choked him until he lost consciousness. He said he is still suffering from dizziness and pains in his chest a week later.

The Chinese diplomats said they had been in communication with local police and that they hoped to be able to focus on returning to their responsibility of supporting Chinese citizens in the UK in a peaceful and safe manner.