A bus driver who was caught on video watching a fight between two women on a transit bus travelling between Surrey and Langley, B.C., is speaking out, saying he tried to break up the fight when he had a chance.

Video of the incident taken earlier this month shows a mother of three pummelling another woman who threw a drink at her baby, after a shouting match erupted at the front of the bus.

The video of the incident was posted on YouTube and has since gone viral on social media.

Now the bus driver seen in the video, Bruce Robertson, says he was compelled to come forward and tell his story because he doesn't want people to think he didn't do anything.

Robertson says when the fight began he was driving along Fraser Highway and then pulled over.

"We're not mandated to physically get involved in a fight, but sometimes you have a moral responsibility. Don't forget these children are still at the front of the bus and their mother is involved in a fight. It can't be a good situation for them.

"The people in the upper deck, as I call it in the back section behind the rear doors, were cheering the mother on."

Robertson says he separated the two women and told the woman who instigated the incident to get off the bus. He says there were 16 passengers aboard and no one got up to help.

The woman, who can be seen being attacked in the video, was later charged with assault and uttering threats after she allegedly threatened to kill the mother and her three children on board the bus.

Leah MacKay, 44, appeared in court last Wednesday charged with one count of assault, two counts of assault with a weapon, and one count of uttering threats.

The mother is not facing charges in the incident, and the court issued a publication ban to protect her children from being identified.

Police said apart from some scrapes and bumps, nobody was seriously injured.

With files from Dan Burritt