Their actions continued throughout the day and, at night, a flash mob appeared at the Cross-Harbour Tunnel tollbooths and set them on fire, as panicked attendants fled in fear. The flames were put out quickly but less than two hours later radicals were back to set them ablaze again.

By night time too, mobs had taken over roads in at least 10 districts, putting up barriers made of bamboo and bricks mounted like Lego blocks, and setting objects on fire.

The man, fighting for his life in hospital on Wednesday night, was among 58 people, aged one to 81, injured on Wednesday.

At Chinese University, where protesters and police engaged in a more than 16-hour stand-off and bitterly clashed at a pedestrian bridge, riot officers were nowhere to be seen on Wednesday.

Protesters had regained control of the bridge, which stands over Tolo Highway, and had reinforced their barricades with more furniture, bins and poles. Bags packed with petrol bombs were lined above the bridge in case police returned.

The highway was empty of traffic as protesters had gained control of the major expressway connecting New Territories towns to the rest of the city.

“U-turn or you pay your price – this is the warning from students of Chinese University!” protesters chanted at any passing car, threatening to throw bricks at drivers who refused to leave the highway.

Protesters had taken over a college on campus and were using its kitchen to serve meals. They converted the stadium into a resting area and a testing field to practise hurling petrol bombs, first by throwing sticks and then with real firebombs.

Five Chinese University students charged with rioting in Hong Kong

Students, graduates and citizens hiked up the hilly campus carting supplies to the protesters. A male protester at Chinese University, who is in his 30s, insisted police had no right to enter and should pledge they would not return “so students can ease their minds”.

But the High Court dismissed an injunction application by Chinese University student leader Jacky So Tsun-fung to ban police officers from entering the Sha Tin campus, ruling that officers were entitled to enter any premises to “prevent a breach of the peace”.

Secretary for Security John Lee Ka-chiu also insisted no place in the city was beyond the long arm of the law. “Universities should not be a place which breed violence,” he warned.

At a police briefing, Chief Superintendent John Tse Chun-chung described the violence of the protesters at Chinese University as a bad omen for Hong Kong.

Stay or go? Hong Kong’s foreign students pack bags amid protest chaos

“We have strong suspicions that the school was used as a weapons factory,” he said.

 Police Senior Superintendent Kelvin Kong Wing-cheung said 1,576 rounds of tear gas, 1,312 rubber bullets, 380 beanbag rounds and 126 sponge-tipped rounds were fired on Tuesday while the other side hurled “hundreds” of petrol bombs, and at Chinese University, at least three flaming arrows.

Since the unrest, sparked by the now-withdrawn extradition bill, began in June, police said they had arrested more than 4,000 people, 39.3 per cent of whom are students and nearly half of them are in tertiary institutions. On Tuesday, the force arrested 142 people.

Mainland students at Chinese University, along with others from foreign countries, left in the growing violence.

By Wednesday, more than 80 from the mainland had left, and were evacuated across the border with the help of Hong Kong’s marine police, while Taiwanese students at the university also received a note from the student association and Taiwan’s Mainland Affairs Council advising them to return home. Dozens of students signed up for the plan.

All across the city, many shops were forced to close as staff could not get to work on time because of the traffic disruption. Apart from the rush-hour service suspension on three key railway lines, the closure of train stations and the cancellation of a horse racing meeting, Hong Kong banks also shut a record 250 branches.

The Hospital Authority said on Wednesday that some hospital and clinical services, including elective surgeries, could be affected as staff could not get to work on time because of the traffic disruption.

After three days of uncertainty for parents on whether to allow their children to attend school amid the chaos, the Education Bureau cancelled all classes from kindergarten to secondary schools on Thursday.

By then, the city’s embattled leader Carrie Lam Cheng Yuet-ngor had already drawn the ire of parents and teachers when she said that the government would be “falling into the trap” of protesters who wanted to paralyse the city if it suspended classes.

Some 10 tertiary education institutions in the city announced further cancellation of classes, or postponement of graduation ceremonies.

At the height of traffic disruptions, train services on the entire East Rail line, Kwun Tong line, Tsuen Wan line, and part of the West Rail line were suspended and 70 bus services ground to a halt because Tolo Highway was blocked.

Education Bureau slammed for delay in suspending classes

Operator the MTR Corporation said the East Rail line had to shut because two trains at Sheung Shui and another at University station were set on fire by protesters in the early hours of Wednesday and Kowloon Tong station was vandalised, and a petrol bomb was thrown on its tracks.

A video circulating online showed a protester being shouted at by other passengers as he was trying to stop a train from leaving Kam Sheung Road station on the West Rail line. Scuffles also broke out at Central, as protesters tried to stop a train from leaving by blocking the doors.

At lunch time, once again, protesters descended onto Central. A few black-clad protesters shattered the glass facade of the Bank of Communications branch on Pedder Street by hurling bricks and then entered the branch to vandalise it. Later, one man was seen scattering the shattered glass onto the road.

Cars, including a police vehicle, were also trapped in a tunnel on Connaught Road Central as protesters rained bricks from above.

Sandra, a medical professional from Germany, confronted protesters setting up roadblocks on Des Voeux Road Central, only to be told off for being a foreigner. “I am a permanent resident here. I am going nowhere. That’s not democracy. In a democracy, you need to listen to both sides,” she said.

On Thursday, protesters are planning to cause mayhem again.

Reporting by Sum Lok-kei, Zoe Low, Chris Lau, Elizabeth Cheung, Karen Zhang, Phila Siu, Jeffie Lam, Chan Ho-him, Alvin Lum, Kimmy Chung, Brian Wong, Clifford Lo, Gary Cheung, Kanis Leung and Tony Cheung