China’s consul general in Manchester and five other diplomats have returned home and will escape questioning by police for their role in the beating up of a pro-Hong Kong democracy demonstrator outside the consulate in the city on 16 October. The Chinese, citing diplomatic immunity, decided to recall the diplomats after the UK Foreign Office gave the embassy a week to make the diplomats available for questioning by British police. Conservative MPs reacted furiously, saying the diplomats should have been kicked out weeks ago, rather than allow the case to drag on for two months. Iain Duncan Smith, a former cabinet minister, said: “The flagrant assault on peaceful democracy protesters in Manchester needs more than allowing those responsible to leave the UK uncharged with their heads held high. Letting China take them back is not justice. We should have kicked them out weeks ago.” Other MPs say the diplomats should have been declared persona non grata given the evidence against them. The departure of the consul general, Zheng Xiyuan, was announced by the UK foreign secretary, James Cleverly, who appears unlikely to take any further action, even though he regards the beatings as disgraceful. The embassy claimed the demonstrators had entered the grounds of the consulate illegally, but video footage shows staff dragging a protester by his hair into the consulate grounds. Zheng later said it was his duty to defend his leader, Xi Jinping. In a statement, Cleverly said: “Images carried on social media showed what appeared to be completely unacceptable behaviour by a number of individuals near the entrance to the consular premises. The right of free expression – including the right to protest and to speak one’s mind – is absolutely essential to our democratic life.” Cleverly said he had asked the Chinese embassy to waive diplomatic immunity to allow the interviews to proceed, but “the Chinese embassy, acting on instructions from Beijing, notified His Majesty’s government that the functions of the consul general in Manchester have come to an end and he has returned to China. “The embassy has further notified us that the other staff involved in the incident who the police wish to interview have either left the United Kingdom or will shortly do so.” Defending his approach and expressing his disappointment that the diplomats had not faced justice, Cleverly said: “We have been clear with China from the outset that we were prepared to take firm action should the police determine that there was a case to charge officials for their involvement in the incident. We expect a certain standard of behaviour from all foreign diplomats and consular staff in the UK regardless of their privileges and immunities”. He added it was right that due process was involved, and the police first undertook their investigation. But the pace of the police inquiry gave the Chinese every opportunity to minimise the incident by sending them home once a formal request to interview them was made. Britain is trying to improve its relations with China, and it may have been that both sides preferred not to worsen what was already an escalating diplomatic incident. British officials said given the seriousness of this matter, it was correct and appropriate for Greater Manchester police to take the decision to begin an investigation. They stressed it was right for the UK to be seen to abide by the rule of law, follow due process and respect the operational independence of our police. Chris Sykes, the assistant chief constable of Greater Manchester police, said the force was continuing its investigation. “They have also successfully identified a number of offences including numerous assaults and public order offences as well as potential suspects and victims that we would like to speak to in connection with the incident. “No arrests have yet been made but our inquiries will continue for as long as necessary with support from partners.” The Vienna convention on consular relations allows states to withdraw members of a consular post at any point. In a letter to Manchester police, Zheng said the protesters had displayed slogans that were “deliberately designed to provoke, harass, alarm and distress our consular staff”. He said the activists were “asked politely” to remove the imagery “but refused to do so”. In another video released previously by the embassy, a spokesperson had said: “Providing shelter to the Hong Kong independent elements will only, in the end, bring disaster to Britain.” He said he wanted to “remind” people of Aesop’s fable about the farmer and the snake, “where the farmer showed sympathy to the snake but finally got bitten”. He spoke at length about how much the UK relied on China as its third-largest trading partner and “number one source of imports”. “British exports to China also increased sharply so we see this relationship to be win-win and mutually beneficial,” he said.