A school bus driver lost consciousness and another passenger was slightly injured when the vehicle carrying about 50 children crashed inside Shing Mun Tunnel on Wednesday afternoon.
The coach was travelling towards Tsuen Wan when it suddenly lost control and struck the tunnel wall at around 3.30pm.
Emergency responders found the driver, a man in his fifties, unconscious at the scene.
A female adult passenger sustained minor injuries to her hand, while the 47 children on board were unharmed.
Both the driver and the injured passenger were taken to Yan Chai Hospital in Tsuen Wan for treatment.