It would have been easy for physical education teacher Khairil Anwar Tahir to dismiss the commotion in Bedok North Road last Wednesday as none of his business.

But when the 39-year-old spotted a man hitting passing vehicles with a hammer, he knew he had to do something.

Concerned that someone would be hurt, Mr Khairil called out to the 66-year-old man, who is believed to be of unsound mind, and tried to distract him. But he appeared to be in a daze, said Mr Khairil.

The teacher then decided to call the police. Minutes later, the police rushed the man to the ground to disarm him. Mr Khairil also helped the officers to restrain the man.

The incident was caught on video which then went viral.

Mr Khairil said he could not ignore the incident, adding: "What if everyone thought someone else had called the police? If I didn't do it, it could have been the case that nobody would do it."

Yesterday, he was presented with the public spiritedness award at Bedok Police Division. Commander of Bedok Police Division Julius Lim commended the actions of Mr Khairil and the officers involved. "(Mr Khairil's) example reminds us that the maintenance of rule of law in Singapore involves not just the police, but everyday Singaporeans too, stepping forward to work hand in hand with police officers to keep our community safe and secure."

Mr Khairil was on the way back to his home in Woodlands from his parents' flat in Chai Chee at about 4pm when he encountered a traffic jam along Bedok North Road.

As he inched forward on his motorcycle, he spotted the man hitting passing vehicles with the hammer.

Leaving his motorbike by the side of the road, Mr Khairil approached the man and tried to engage him.

Within minutes, he was joined by officers from Bedok North Neighbourhood Police Centre and the Public Transport Security Command.

In the group was Sergeant Lee Wei Liang, 23, who was the officer seen in the video tackling the man to the ground. "He was distracted and I was confident that I could neutralise the threat," he said of his calculated move.

With the help of Mr Khairil and fellow officers - Special Constabulary Sergeant Quinnlan Zaini Hassan, 20, and off-duty Sergeant Wong Cheuk Kay, 25 - Sgt Lee managed to subdue the man.

A day after the incident, the man was charged with committing a rash act that endangered the lives or the safety of others.