Cameron's coded message for China
If I were not here, David Cameron will tell Chinese students later, I would be back in the House of Commons facing questions from an opposition party whose constitutional duty is to hold the government to account.
Britain, he insists, is stronger for that and as a result of having powerful independent courts and media.
The prime minister clearly hopes that this will not be seen merely as a civics lesson from a distinguished visitor but as advice about China's future development.
Diplomatically, his speech echoes the assertion of the Chinese Communist Party that the country's history and its vast size make it different, but he still asserts that "the best guarantor of prosperity and stability is for economic and political progress to go in step together".
What he does not say is that if he were Chinese and campaigned for these views he could well end up in prison. Nobel Peace Prize Winner Liu Xiabo was sentenced to 11 years in jail for publishing a political manifesto which was seen as a threat to the stability of the state.
I understand that the prime minister did raise Mr Liu's case with Premier Wen at a banquet on Tuesday night - but how vigorously no Chinese student nor British voter is likely to ever know.
I will be watching carefully to see whether the Chinese media report the political content of the prime minister's speech or merely relay his praise for China's economic development.
Beijing has changed dramatically since I first travelled here with Tony Blair. The bikes have been replaced on the streets with traffic gridlock.
The streets, once grey, are full of the colour of Western commercialism mixed with the buzz of Chinese entrepreneurship. Back then the bars of Western hotels were full of secret police.
On Tuesday, I interviewed the dissident Ai Weiwei in full public view on a busy street. He condemned the prime minister for failing to condemn the Chinese government.
What has not changed though is that the Chinese will not tolerate calls for a change to their one-party state either from their own people or a distinguished visitor - except, that is, in code.
Update, 10:33: The test of David Cameron's message may turn out to be whether anyone beyond the hall at Peking University actually heard it. China TV may choose to report his praise for their country and even the call made by one questioner for lower tuition fees for students coming to the UK. But somehow I doubt whether they will report the PM's call for greater political openness. The Chinese propaganda ministry has even recently censored their own premier's speeches and interviews.