We've hidden his face and obscured his voice to protect his identity

He's one of the millions of Hong Kongers taking to the streets

Many people here are wearing face masks

People are hiding their identities

They fear that the government will press charges

What started as a protest against an extradition bill...

...has become the most serious challenge...

...to the Communist Party's authority...

...since the Tiananmen Square protest three decades ago

As the demonstrations enter a third month...

...neither the government nor the protesters is willing to back down

Police fire tear gas, rubber bullets...

...and use their police baton to hit the protesters

But it's not enough to deter the demonstrators

So what happens now?

This is a real nightmare for the Communist government in Beijing

They can either crush Hong Kong...

...or they can tolerate being defied...

...in a way that undermines everything...

...about their whole structure of government

They have no good choices

Hong Kong is one of the most important financial centres in the world

And it has a unique status

It's a city in China but it's not entirely Chinese

It has its own currency...

...its own passport…

...its own legal system

There's even a boundary between Hong Kong and the rest of China...

...and you need a permit to cross it

This is all down to its history

In 1842 Hong Kong was ceded by the Chinese to the British...

...after the first Opium War

But in 1997 Britain gave it back to China

Hong Kong people are to run Hong Kong

With one important condition...

...for 50 years Hong Kong was to be governed...

...under what is known as “one country, two systems”

The chief executive who runs Hong Kong...

...would be appointed by a pro-Chinese committee

But the city was guaranteed a high degree of autonomy...

...with its own government, legal system...

...and economic independence until 2047

Over the past decade those rights have been eroded

Fuller democracy, promised as part of the handover agreement...

...has yet to be granted by China

Yellow ribbon means come back, come back democracy

Emily Lau was a Hong Kong politician for 25 years

Today she still campaigns for democracy

Things have deteriorated fast...

...particularly since President Xi Jinping came to power

So people are very concerned

We want freedoms, we want personal safety...

...we want the rule of law

China's grip has got ever tighter

In 2012 the government tried to install...

...a patriotic pro-Chinese education system

Then five Hong Kong booksellers...

...who sold material banned in mainland China disappeared

In 2016 pro-democracy opposition leaders...

...were thrown out of Hong Kong's parliament...

...for insulting China when swearing their oaths

And then in February this year...

...the government introduced a bill...

...which would have allowed extradition to the mainland

Very few people in Hong Kong imagine there's going to be...

...full-on, Western-style democracy

But they are very angry about the way that...

...what they believe they were promised...

...was something much more accountable where...

...you'd have something close to universal suffrage

The basic social contract...

...between the people of Hong Kong and their government is breaking down

All this is fuelling the protesters' anger

The invisible hand from China...

...are getting more visible

They are putting more controls on Hong Kong's autonomy and democracy

Hong Kong is not China

People will say to you, “We know that 2047 is coming one day...

...but we don't want it to happen now”

As the protests get larger and more violent...

...the chance of China intervening increases

Beijing has made thinly veiled threats to send in its military forces...

...the People's Liberation Army

Those who play with fire will perish by it

At the end of the day, they will eventually be punished

A few weeks ago nobody seriously thought...

...we could see another Tiananmen Square in Hong Kong

Now you can't rule it out

In 1989 a student demonstration in Beijing ended in massacre

Hundreds, maybe thousands, were shot dead

For the Chinese government...

...the Hong Kong demonstrators are defying the authority...

...of a Communist leadership that cannot tolerate defiance

For President Xi Jinping...

...his kind of north and south, his east and west, is the absolute authority...

...and total control of the Chinese Communist Party

And anything that threatens that must be crushed

They are afraid that it could be very infectious...

...and they don't want to see such marches...

...in the other parts of mainland China

Another fear is some protesters' demand for full independence

But military intervention would be a very risky strategy for Beijing

Hong Kong for all its woes...

...is still a very rich world financial centre

To roll troops into that kind of financial centre...

...would be an economic catastrophe

In 1993 Hong Kong's GDP accounted for...

...more than a quarter of mainland China's

Today China's remarkable rise means that Hong Kong's...

...economic output makes up less than 3% of the mainland's

But Hong Kong remains important for China

Multinationals use it as a launch pad to the mainland...

...and it gives Chinese companies access to the rest of the world

So we are very special

We are a window for China to look to the outside world...

...as an international city with all our connections

It's very valuable to China

So how the turmoil is resolved matters to more...

...than just the people of Hong Kong

The government there said the People's Liberation Army may be deployed

But if that's the case, the game is over

If China uses lethal force...

...then you would see an economic crash

There's 85,000 American expatriates in Hong Kong

You would see them fleeing for the airport

This all comes at a time when China and America...

...are waging a trade and technology war

Bloodshed on Hong Kong's streets...

...would make relations deteriorate even further

Beijing is now blaming outsiders for the trouble

We've seen remarkably explicit...

...state-media commentaries telling the people of China...

...that these protests are not just radical and violent...

...but are also orchestrated by foreign forces

The Chinese government resolutely opposes...

...any foreign forces attempts to intervene in Hong Kong affairs

For the Chinese Communist leadership...

...what's happening in Hong Kong is evidence...

...that as China rises as one of the world's most powerful countries...

...that the West is using every means possible to divide and to frustrate China

For China the situation has become much more than a dispute over a law

It's become an existential threat

Bruce and the other protesters are holding their breath

I still worry what happens next...

...because the situation could deteriorate very rapidly

China's Communist rulers must choose between two mortal dangers...

...the collapse of economic stability and prosperity...

...or the acceptance that protests can limit the Party's absolute power