British officials knew in advance that the Chinese government was preparing to kill student protesters at Tiananmen Square in 1989—and their intelligence didn’t come at the last minute. Indeed, a telegram sent to Margaret Thatcher's administration from Britain's ambassador to China on May 20, 1989—the same day Chinese leader Deng Xiaoping declared martial law—quoted Deng as saying "200 dead could bring 20 years of peace to China." Sir Alan Ewen Donald was repeating what had been told to a US expert on China, with whom he'd just had lunch, per Quartz. He said the Pentagon had also concluded that Deng saw "no way to avoid bloodshed" and had instructed the military "to do what is necessary to put down the situation."

"The implication clearly was that the sacrifice of a number of demonstrators [sic] lives now would stabilize the present situation and buy the time needed to complete the reform of China," Donald wrote. The revelation of the UK's intelligence—which one reporter describes as "stunning"—comes from the Dec. 30 release of scores of government files from 1989 and 1990, which were previously classified. Two weeks after Donald's telegram was sent, the People's Liberation Army shot and killed hundreds of unarmed students occupying Beijing's Tiananmen Square in protest of recent violence against pro-democracy demonstrators. Prime Minister Thatcher at the time said she was "shocked and appalled by the shootings," reports the Independent. (China's last Tiananmen prisoner just went free.)