It was Sherlock Holmes who once said “When you have eliminated the impossible, whatever remains, however improbable, must be the truth”.

On this basis I am able to say with almost complete confidence that only the leaders of the pan democratic movement are able – if they so choose, and I hope they will – to bring the present widespread public disorder in Hong Kong to a gradual halt. The odds may be against them, which we can discuss in a moment, but it is already clear that nobody else stands a chance.

Start with the Central People’s Government in Beijing. Every large-scale protest movement since the handover has at its core a fundamental distrust – whether merited or not -- of the CPG’s motives. The draft national security legislation in 2003, proposals for national education curriculum in 2012, ruling by the National People’s Congress to restrict pace of political reform in 2014, all have this feature in common. In the background there have been many complaints over the same period about the massive influx of mainland tourists -- dubbed unkindly “locusts” by some – plus repeated calls for the one-way permit system to be revised and with a cut in numbers. The CPG as the sovereign state does of course hold absolute power in that it could destroy our city and way of life at a stroke, but that is hardly conducive to prosperity and stability. Against that backdrop, does it really have scope to initiate positive change that would be accepted at face value? Probably not, though as we shall see it does have the ability to respond positively if others make the first move.

Next the role of the SAR government. The mere recitation of the list above makes the failure to foresee the strength and vehemence of opposition to the extradition proposals even more extraordinary. And at every stage of the current saga when a concession has been reluctantly offered it has been a case of “a day late and a dollar short”. After one million marched, the administration waited just two hours before declaring the second reading of the bill would proceed. When our young people blocked off access to the Legislative Council – literally using their bodies to stop passage of the legislation – its progress was “postponed” rather than cancelled. Even after nearly two million marched, the administration refused to use the word “withdrawn”.

The government, sad to say, now has no credibility whatsoever, and no ideas about how to take matters forward. Officials promise to listen harder, but then completely ignore the advice of the Bar Association and the Law Society on legal issues. They brush aside a comprehensive conciliatory package suggested by the former chief justice, an exceptional and brave political intervention on his part, and pay no heed even when the foremost business organisation – the General Chamber of Commerce – breaks ranks and advocates the same thing. Clearly there is something wrong with official ears.

The police force here is not a political playmaker, rather a victim of the political paralysis. It is grossly unjust that its members should be thrust into the melee with no proper game plan behind them. There have been some instances of over-reaction, but it is completely wrong for individuals to be attacked on social media by name and to have their families drawn in as well. It will take many years for the force’s reputation to recover from the abject failure to protect the public at Yuen Long MTR station. Armed policemen reluctant to intercede in a mob attack, and reinforcements slow to arrive? This incident alone merits its own Commission of Inquiry along with the more general one which is surely now inevitable.

Can we look to the protesters to moderate their own behaviour? It seems unlikely. On the contrary, not content with the extraordinary success of the biggest and completely peaceful demonstration in Hong Kong’s history on 16 June, crowds of mostly young people then risked losing the goodwill earned by laying siege to police headquarters and other government buildings, culminating in the trashing of Legco on 1 July. Plans have been announced for a programme of demonstrations running through August. To what purpose? Meanwhile, there is no justification for childish behaviour such as disrupting public transport during peak periods. And desecrating graves, whatever the provocation by the living, is simply uncivilised.

Part of the problem is the lack of leaders with whom to negotiate. None are in a position to bind their followers. Even though the BBC and CNN always run to interview Joshua Wong Chi-fung, it is worth remembering that he did not attend either of the two biggest marches in our history – because he was in jail. It is also worth remembering that he was imprisoned not for protesting but for defying a direct order from the court. So much for dedication to the rule of law.

Having eliminated the impossible, we are now driven to consider the implausible. What should the senior pan dems be doing? They can start by displaying some leadership and speaking the truth to all parties. First, stop the implicit endorsement of violence by protesters. Making excuses for it, or just remaining silent is not good enough. Secondly, make it clear to all and sundry that independence is a chimera, it is never going to happen, you do not support it and continued pursuit of it is a waste of everyone’s time and energy. Third, you must publicly on the record accept China’s sovereignty over Hong Kong and decry actions which deface symbols of that sovereignty. Fourth, you must call for a halt to the marches. Yes, people have a right to demonstrate but there comes a time when the point has been made and it is time for things to cool down. Most people now need to get on with life and the police are exhausted.

Now the leaders may feel that many demonstrators will ignore their advice and by urging moderation they will lose credibility. This is short-term thinking at its worst. When things settle down – and they will – people will remember who was courageous enough to speak up for common sense. And Beijing will have a credible party with whom to discuss the next phase of political reform.