While the tunnel has been declared fit to reopen, PolyU remained locked down by police on Tuesday, as university search teams fanned out to check rooms in every building, looking for protesters still hiding there.

Only one woman was found after the day-long search, and the university could not tell if she was the last one left.

More than 1,100 protesters and their supporters have emerged since police sealed all campus exits on November 17. Those over 18 were arrested, while about 300 minors had their details recorded. A number of others managed to escape.

Police gave an assurance on Tuesday that none of those found on campus and requiring medical attention would be arrested on the spot, even if they were adults.

Hong Kong drivers may use tunnel for free while torched toll booths are repaired

The Cross-Harbour Tunnel is the city’s most widely used of three tunnels, with about 110,000 private and public vehicles crossing daily.

He said about 800 government and contract employees worked day and night for 100 hours to get the tunnel in shape to be used safely again. “The site was like a war zone attacked by bombs. It’s really a miracle that all the equipment is now ready for operation.”

While the tunnel was closed, the government provided free ferry services between Hung Hom or Kowloon City and Wan Chai. Cheung said these would continue until Friday evening to “offer a buffer” of support for commuters.

All four lanes of the tunnel, as well as seven automatic and nine manual toll booths, are expected to be operational on Wednesday morning.

Main roads connecting to Hung Hom and Wan Chai will also reopen. Only the middle lane of the Cheong Wan Road flyover will be closed on Wednesday.

Traffic police, two fire engines and an ambulance will be stationed at each end of the tunnel when it reopens.

Diane Wong Shuk-han, deputy director of the Food and Environmental Hygiene Department, said 42 tonnes of debris were cleared from the tunnel and nearby roads.

“We have sprayed water and detergent to remove tear gas residue, oil stains and other toxins,” she added.

Cheung did not give an estimated cost of the repairs, saying the priority was to ensure safety when the tunnel reopened. He said its fire prevention, ventilation and other monitoring systems were damaged, and parts of the highway leading to the crossing also had to be repaired.

Cheung added there was little that could be done to safeguard the tunnel from similar vandalism in future, but police remained ready to step in if necessary.

Appealing to the public to condemn the use of violence, he said: “Destruction is easy, but construction is hard. We have to urgently restore peace and stop violence.”

Hong Kong drivers may use tunnel for free while torched toll booths are repaired

The tunnel closure led to congestion at the alternative Eastern Harbour and Western Harbour tunnel crossings.

Quentin Cheng Hin-kei, spokesman for the commuter concern group Public Transport Research Team, said the disruption added about 30 minutes to the travelling time of commuters trying to get from Kowloon or the New Territories to Hong Kong Island.

“The closure of the Hung Hom tunnel has caused great inconvenience to passengers and drivers,” he said.

His group had no concerns about the reopening of the tunnel. “If the government confirms that it is safe for operation, we can be assured that officials have thoroughly inspected and tested all relevant facilities,” he said.

Meanwhile, the litter-strewn PolyU campus remained a scene of damaged and vandalised buildings on Tuesday, after the chaos of the past two weeks.

A group of 50 senior staff members, counsellors and paramedics split into seven teams which searched every room on the Hung Hom campus from 10am to 4pm.

PolyU vice-president Alexander Wai Ping-kong said they could not be sure if the sole woman they found was the last person hiding there.

The young person, who was over 18, was found lying on a sofa near the student union office. She appeared weak and emotionally unstable, but a medical examination found her normal. A counsellor accompanied her out.

Wai said the teams found various dangerous chemicals and petrol bombs scattered all over the campus.

The university would decide its next move, he said, which might include another sweep of the campus on Wednesday.

“If we believe that everyone has left, the next step will be to remove all the dangerous chemicals on campus before it can reopen,” he said.

Protest-hit tunnel could reopen in a week, Hong Kong government says

A police team remained on standby to enter the campus, but Wai said whether it went in would be a mutual decision between the university and officers.

Since Monday, top brass of PolyU have repeatedly appealed to the government and police to end the lockdown of the campus, which they said was in a state of “utter chaos” and also a hygiene and health risk.

PolyU was occupied by more than 1,000 masked radicals and their supporters about two weeks ago, as Hong Kong’s anti-government protests shifted from the streets to university campuses.

The police lockdown began on November 17, after intense, violent clashes there.

Following PolyU’s appeals to end the siege, police announced on Monday night that they had assembled a team of negotiators from the force, school principals, psychologists and others to enter the campus and persuade the remaining protesters to leave.

There were estimates of between 30 and dozens still believed to be hiding there, refusing to emerge for fear of being arrested or mistreated by police.

“We will only enter the campus at an appropriate time, hoping not to provoke people inside,” she said. “I hope the group doesn’t need to be deployed, if PolyU’s working team can successfully persuade people to leave the campus safely. The mission is still about persuading them to come out.”

Lam said she was aware of the tension between police and protesters, and that was why they had adopted “cooling” measures.

A police source said it was the university that did not want the police team to enter the campus “as they did not want to be seen as betraying the students”.

But vice-president Wai denied that, saying both police and the university came up with the idea of searching the campus at the same time.

“We are not pre-empting anybody,” he said.

Additional reporting by Tony Cheung and Kathleen Magramo