Ling was pronounced dead on arrival at Fanling Hospital on September 19 last year.

The incident occurred just after the bus left a Hong Lok Yuen roundabout.

Driver Li Wai-cheung continued to drive the route 70X bus at a speed of 25 to 30 km/h along Tai Wo Service Road West towards Fanling until a passenger told him someone had fallen out of the bus.

After the jury returned a verdict of death by accident, Coroner Warner Banks said: ''There are millions of passengers travelling on buses each year. This is the first such incident which I have come across in the four years that I have sat in the Coroner's Court.'' A postmortem examination report concluded that Ling died of a skull fracture and brain injuries.

A motor vehicle examiner at the Kwai Shing Vehicle Pound, Lau Wai-kwok, testified the emergency window fell out because its hinge rivets had been sheared off.

The jurors recommended that public bus companies should carry out regular checks to ensure emergency exit doors and windows were properly fixed to the body of buses.

They also suggested companies install clear signs near all emergency exits telling passengers the exits were only to be used during emergencies.

According to police, the Kowloon Motor Bus Company and its driver, Mr Li, will stand trial on June 10 for allegedly using a vehicle not in a good and serviceable condition.

Chung Chu-wing, a passenger, said he was sitting three rows from the back of the bus when he noticed a man - later identified as Ling - sitting nearby, coughing.

''The man stood up. He walked towards the rear emergency window, opened the latch and pushed open the window. He stretched his head out quite a bit. At that time I thought he was trying to vomit,'' he said.

''I noticed his right foot was also a little bit over the window. He placed his foot on the window-sill and fell out of the bus, together with the emergency window,'' Mr Chung said.

Mr Li said he immediately stopped the bus when a passenger shouted at him to stop. He got off the bus and saw Ling and the emergency window lying 80 metres behind the vehicle on the Fanling-bound traffic lane.

A government laboratory chemist, Dr Kwok Fu-chiu, said one of the 21 rivets was missing from the emergency exit window, five were partially broken and the rest completely broken, due to corrosion.

He said the five rivets would not have been sufficient to hold the weight of the window and Ling.