BEIJING, June 4 – The most senior Chinese official jailed for sympathising with the 1989 Tiananmen Square protests has urged the leadership to come clean on why the pro-democracy movement was crushed.

The demonstrations that drew more than a million people on to Beijing's streets ended in a military crackdown on June 4 of that year. Now a fading memory – or no memory at all for young people – the massacre is still taboo in the Chinese media.