The death toll from the 1989 Tiananmen Square massacre was at least 10,000 people, killed by a Chinese army unit whose troops were likened to “primitives”, a secret British diplomatic cable alleged.

The newly declassified document, written little more than 24 hours after the massacre, gives a much higher death toll than the most commonly used estimates which only go up to about 3,000.

It also provides horrific detail of the massacre, alleging that wounded female students were bayoneted as they begged for their lives, human remains were “hosed down the drains”, and a mother was shot as she tried to go to the aid of her injured three-year-old daughter.

Written on 5 June 1989 by Sir Alan Donald, the then-British ambassador to China, the hitherto secret cable has now been placed in the UK National Archives at Kew, where it was found by the news website HK01.

The ambassador said his account of the massacre of the night of 3-4 June was based on information from a source who had spoken to a “good friend” in China’s State Council, effectively its ruling cabinet.

The State Council member, Sir Alan said, “has previously proved reliable and was careful to separate fact from speculation and rumour”.

In unflinching detail, Sir Alan told London that the “atrocities” against thousands of pro-democracy protesters in and around Beijing’s Tiananmen Square had been coordinated by the 27 Army of Shanxi Province, whose troops he described as “60 per cent illiterate and called primitives”.

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Sir Alan said previous waves of troops had gone in unarmed to disperse the protesters, many of whom were students.

Then, Sir Alan wrote, “The 27 Army APCs [armoured personnel carriers] opened fire on the crowd before running over them. APCs ran over troops and civilians at 65kph [40 miles per hour].”

Sir Alan added: “Students understood they were given one hour to leave square, but after five minutes APCs attacked.

“Students linked arms but were mown down. APCs then ran over the bodies time and time again to make, quote ‘pie’ unquote, and remains collected by bulldozer.

“Remains incinerated and then hosed down drains.”

Dying for democracy: Tiananmen Square, remembered Show all 29 1 / 29 Dying for democracy: Tiananmen Square, remembered Dying for democracy: Tiananmen Square, remembered Students stand to attention on the Monument to the People's Heroes in Tiananmen Square in Beijing today Getty Images Dying for democracy: Tiananmen Square, remembered A Chinese citizen stands passively in front of tanks on the Avenue of Eternal Peace in this photo taken during the crushing of the Tiananmen Square uprising. The tanks did not slow down, but they did turn around him before taking up positions in another part of Beijing. REUTERS/Str Old Dying for democracy: Tiananmen Square, remembered A group from the crowd of 200,000 pro-democracy student protesters stand face to face with policemen outside the Great Hall of the People in Tiananmen Square, 22 April 1989 in Beijing as they take part in the funeral ceremony of former Chinese Communist Party leader and liberal reformer Hu Yaobang during an unauthorized demonstration to mourn his death. Hu Yaobang's death in April trigged an unprecedented wave of pro-democracy demonstrations. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Students gesture and shout slogans as they pay respects, 22 April in Beijing, to former Chinese Communist Party leader and liberal reformer Hu Yaobang, as thousands of students gather near the monument to the People's Heroes in Tiananmen Square. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered 14 May 1989 - several hundred students staging a huge demonstration at Tiananmen Square as they start an unlimited hunger strike. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Chinese worker shouts pro-democracy slogans during a mass rally in Beijing streets 17 May 1989. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Paramedics evacuate ailing student hunger striker from Beijing University on 17 May. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Chinese workers parade through Beijing streets, 18 May, in support of student hunger strikers gathered at Tiananmen Square. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered 18 May 1989 - students from Beijing University during a huge demonstration at Tiananmen Square as they start an unlimited hunger strike as the part of mass pro-democracy protest against the Chinese government. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Pro-democracy demonstrators surround a truck filled of People's Liberation Army (PLO) soldiers, 20 May, on their way to Tiananmen Square after Martial Law was proclaimed in Beijing. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Pro-democracy demonstrators raise their fists and flash Victory signs, 20 May, as they stop the military truck filled with soldiers on its way to Tiananmen Square after Martial Law was proclaimed. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Waving banners, high school students march in Beijing streets near Tiananmen Square, 25 May, during a rally to support the pro-democracy protest against the Chinese government. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Raising a banner which reads 'Lift Martial Law and Protect the Capital', journalists from the Communist party's official newspaper, the 'People's Daily'. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered A student shows off a stick to which is tied a broken bottle with the picture of Chines leader Deng Xiaoping as thousands of demonstrators gathered in Beijing streets near Tiananmen Square, 25 May, during a rally to support the pro-democracy protest against the Chinese government. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Using a loudspeaker, a student asks soldiers to go back home as crowds flooded into the central Beijing, 3 June. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Exhausted, humiliated soldiers are hustled away by Beijing people in central Beijing, 3 June 1989. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered A dissident student asks soldiers to go back home as crowds flooded into the central Beijing, 3 June. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Citizens and students flash 'V'-signs to celebrate their victory after forcing tens of thousands of troops to retreat from central Beijing, 3 June. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered The soldiers of the PLA are forced by dissident students to sit in front of the Great hall of the People at Tiananmen Square, 3 June CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Dissident students and workers armed with wooden sticks gather outside the Great hall of the People at Tiananmen Square, 3 June, shouting slogans demanding the ousting of Premier Li Peng. CATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Beijing residents inspect the interior of some of over 20 armoured personnel carrier burnt by demonstrators to prevent the troops from moving into Tiananmen Square, 4 June MANUEL CENETA/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered One of over 20 armoured personnel carrier burnt by demonstrators to prevent the troops from moving into Tiananmen Square, 4 June MANUEL CENETA/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered PLA soldiers leap over a barrier on Tiananmen Square in central Beijing 4 June, during heavy clashes with people and dissident students. ATHERINE HENRIETTE/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Taken care by others, an unidentified foreign journalist (2nd right) is carried out from the clash site between the army and students, 4 June, near Tiananmen Square. THOMAS CHENG/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered A girl wounded during the clash between the army and students, 4 June, near Tiananmen Square is carried out on a cart. MANUEL CENETA/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered Two injured during the clashes on 4 June are carried out. MANUEL CENETA/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered A Beijing resident on the west side of Tiananmen Square shows a slug from an automatic rifle fired by the army, 4 June, that went through his flat's widow in central Beijing. MANUEL CENETA/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered The PLA tanks guard a strategic Chang'an Avenue leading to Tiananmen Square, 6 June MANUEL CENETA/AFP/Getty Images Dying for democracy: Tiananmen Square, remembered A protestor stands passively in front of tanks on the Avenue of Eternal Peace, 5 June, during the crushing of the Tiananmen Square uprising. The tanks did not slow down, but they did turn around him before taking up positions in another part of the city. REUTERS/Str Old

Sir Alan’s cable stated that the violent repression of the Tiananmen Square protests occurred after some members of China’s State Council had come to consider that civil war was imminent.

Sir Alan reported as speculation that Deng Xiaoping’s Communist government chose the 27 Army for the operation because its troops were “the most reliable and obedient”.

He reported that from what he had been told, 27 Army troops had used dum-dum bullets and “snipers shot many civilians on balconies, street sweepers etc for target practice”.

“27 Army ordered to spare no one,” he wrote. “Wounded girl students begged for their lives but were bayoneted.

“A three-year-old girl was injured, but her mother was shot as she went to her aid, as were six others.”

The cable also alleges that the massacre continued even after the first wave of killings.

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Sir Alan wrote: “1,000 survivors were told they could escape but were then mown down by specially prepared MG [machine gun] positions.

“Army ambulances who attempted to give aid were shot up, as was a Sino-Japanese hospital ambulance. With medical crew dead, wounded driver attempted to ram attackers but was blown to pieces by anti-tank weapon.”

In another incident, the cable said, the troops even shot one of their own officers.

Sir Alan wrote: “27 Army officer shot dead by own troops, apparently because he faltered. Troops explained they would be shot if they hadn’t shot the officer.”

The final sentence of Sir Alan’s cable reads: “Minimum estimate of civilian dead 10,000.”

This estimate is way above any figures issued by the Chinese government, which has numbered the civilian dead at between 200 and 300.

There has never been an undisputed figure for the death toll, but on early on the morning of 4 June, the Chinese Red Cross estimated that 2,700 people had been killed.

This is still way below the figure suggested by Sir Alan, but most reports of the massacre now go with the Red Cross number or something close to it.

In 2014, however, it was reported that a confidential US government file quoted a Chinese military source as saying the Communist regime’s own internal assessment believed 10,454 people had been killed – a figure that would fit Sir Alan’s initial estimate.

The Chinese government has always characterised the response to the Tiananmen Square protests as legitimate defence against a counter-revolutionary riot or rebellion.

On the night of 3 June, United Press International reported that a statement was repeatedly broadcast on Chinese television, claiming: “Tonight a serious counter-revolutionary rebellion took place. Thugs frenziedly attacked People’s Liberation Army troops, seizing weapons, erecting barricades, beating soldiers and officers in an attempt to overthrow the government of the People’s Republic of China.

“For many days, the People’s Liberation Army has exercised restraint and now must resolutely counteract the rebellion.