One of the most profoundly disappointing responses to the events in Hong Kong has been Britain’s silence – or its weak words that have sometimes been worse than silence.

At the very least, Britain should act honourably: it has a moral and legal responsibility to Hong Kong. It did after all sign a treaty, back in 1984, that guaranteed Hong Kong’s core values and way of life, including freedom of speech and assembly, until 2047.

The truth is that money talks. Talk to British business people and their first instinct is to keep their heads low; they just want things to carry on as before, would like the protests to disappear, and maintain good relations with China. The view from the British government is not much different.

In fact, I’ve been surprised at the basic lack of knowledge at the Foreign Office. There doesn’t seem to be anybody there who knows Hong Kong, who knows what makes the place tick. Nor is there anybody who can make the argument that the interests of the Hong Kong people might also be good for British interests, indeed the interests of the world at large.

On a personal level, I feel very saddened. I was wheeled out at the time of the handover, when everyone was keen to instil confidence, everyone keen to emphasise that it was just about a change of flag.

It’s worth reminding the British people that John Major made a pledge before the handover that Britain would do everything possible to ensure that the terms of the joint declaration were adhered to. At the time of the handover, the then foreign secretary, Robin Cook, reiterated that Britain would use its clout to defend Hong Kong and its freedoms. But where are the public comments from the British condemning China? I wonder even if much has been done in private. At heart, the protests in Hong Kong are not just about democracy. They are about honouring a promise, Beijing’s promise to the people of Hong Kong to give us genuine one person, one vote for the election of our chief executive in 2017.

Instead, our own government has taken Hong Kong through a sham consultation and we now have a very rigid framework handed down by Beijing that in effect says to the people of Hong Kong: you can have one person, one vote, provided we pre-screen all the candidates so that we are 100% in control of the final outcome. This is in no way acceptable.

Hong Kong’s chief executive, Leung Chun-ying, has taken us through a sham consultation. The report he presented to the Chinese leaderships was dishonest and misrepresented the sentiments of the Hong Kong people.

If he had any courage, he should have presented the mainland leadership with the truth. They could still have chosen to ignore the will of the Hong Kong people, but at least his document would have been an honest one. But he’s clearly in the pockets of Beijing, which put him in place. Leung Chun-ying and his team have little credibility left and will find it increasingly difficult to govern Hong Kong.

I genuinely did not think at the time of the joint declaration that it would turn out this way. I thought that the co-signatories, Britain and China, would honour all the promises laid down in the treaty and guarantee Hong Kong “one country, two systems”. This included guaranteeing: independence of the judiciary, the rule of law and our rights and freedoms and, in particular, that we would move steadily towards genuine universal suffrage.

In all of this, it is too easy to suggest China was always going to behave in this fashion. Chinese leadership is not monolithic and at the very least one needs to assert one’s own interests. And we can be sensible in what we ask for.

From the Chinese perspective, the leadership faces such daunting, fantastic challenges. Strong economic growth was always going to be the main justification for maintaining the legitimacy of one-party rule.

If people are fearful of their future, they are more likely to protest. And of course the Chinese leadership worries about protests spreading. In this light, they might view Hong Kong as an agent of change. So I understand mainland Chinese fears. But if they are allowed to walk away from their commitments under an international treaty, then it doesn’t say very much for China’s commitment to the rest of the world.

Also, they ought to realise that the best way of securing Hong Kong’s long-term prosperity and stability is by allowing one person, one vote. We should also remember the positives of the protests. The Hong Kong people everyone has seen on the streets have been very reasonable, peaceful, despite some, at times, terrible provocation.

The protests have also allowed the world to see a different, younger Hong Kong. I call this the egalitarian generation – most people are not connected with making money. (In truth, this is how outsiders still see Hong Kong, understandably perhaps.)

Many of these young people only know life after Chinese rule. They are worried about many of the same things that worry young people in Britain and elsewhere. Will they find a good job? Will they ever be able to buy a home?

For them, the big change in Hong Kong since I was their age is perhaps the decline in social mobility. In earlier decades, there was great social mobility – if you worked hard, you could move swiftly up the social ladder. There was a certain sense of cohesion.

Now within the territory there is a sense of them and us. Those who make money are tempted to stay quiet, to maintain their links, their status. The rest, they want what many people want across the world – a good education and an open society.

Anson Chan was the chief secretary in both the British colonial government of Hong Kong – de facto deputy to the last British governor, Chris Patten – and the Hong Kong Special Administrative Region government under the Chinese rule