My Take | It's Chris Patten against David Cameron on Hong Kong, not Tung Chee-hwa

This week, the last governor of Hong Kong and the first chief executive of the SAR both spoke on Beijing's proposed plan for the city's constitutional reform.

Chris Patten likened Beijing's plan to the stage-managed democracy in Iran, while Tung Chee-hwa said it would lead to a "real and substantial" democratic reform. Naturally, the media pitted the two men against each other to represent the opposing sides over political reform. Both men are highly intelligent; their personal integrity and sincerity are beyond reproach. But they are talking past each other.

Tung is a state leader and is merely putting a human face to the harsh reform package handed down by the National People's Congress Standing Committee. Now there is no need to insult the Iranians, who don't have a dog in the fight. The question that Patten raises actually has more to do with Britain than Hong Kong, and he says as much. "My comments are not directed principally to Beijing or Hong Kong," he wrote in the Financial Times. "What a former governor can more legitimately do is to invite an interrogation of Britain's sense of honour."

But does Britain still have a dog in the fight? That's a question to be disputed not between Patten and Beijing, for whom he was once "a sinner of a thousand epochs" - a fact now utterly irrelevant - but between Patten and David Cameron. The British prime minister has long concluded there is little to be gained fighting China over Hong Kong and prefers to further his country's trade and commercial interests with the country - hence nary a word about the city or China's human rights when Premier Li Keqiang visited London in June to sign trade and investment deals worth £14 billion (HK$178 billion).

Besides being a former colonial master, Britain is also a party to the Sino-British Joint Declaration. So Patten is right that Britain has moral and treaty obligations towards Hong Kong. But it's an entirely different question whether they can be translated into any material influence. With China's economy now four times that of Britain, Beijing and Cameron have both concluded the former empire has little or no leverage at all over the rising power.

In effect, Patten is asking Britain to take a noble stance - that of Don Quixote.