He must have been peed off.

In an incident of what can only be dubbed urine rage, an Ottawa couple say their car was rammed by a taxi driver they caught taking a whizz against a wall at a south-end mall.

Paul Gallien and his wife, Chia-Chin Hsin, were driving behind South Keys Mall Tuesday when they spotted the driver taking a leak.

The couple was disgusted.

"It's lewd," says Gallien, 36. "It was blatant. He was peeing right there against the wall. I was just being a good citizen. I'd feel bad if I ignored it."

Gallien pulled over and told the driver -- politely he insists -- not to urinate in public in broad daylight.

The man responded with a stream of invective as pungent as his pee.

"He got very aggressive," Gallien says.

"He threatened us with violence. He threatened to urinate on us."

Then the cabbie pointed his taxi at the couple's Chevy Optra.

"He all of a sudden went at us. He hits our car with his taxi," Gallien said.

When the pregnant Hsin got out of the car to protest, the cabbie hit their car again as her husband called 911.

"I couldn't believe it," she said. "I was standing beside the car. I was stunned. I had no idea what he was going to do next."

City police took a statement -- and the cab's licence plate number -- and are investigating, a spokeswoman said.

The couple describe the cabbie as 40, 5-foot-10 to 6-feet tall and heavy-set with balding dark hair. He may have had facial hair.

If the couple calls 311 with all the details, taxi regulators will be on the case, too, says director of bylaw services Susan Jones.

"It's a privilege to have a licence," Jones says. "Inappropriate conduct we definitely would and will investigate. The individual involved is at risk of having his licence suspended or revoked if it's proven."

A single taxi can be driven by half-a-dozen drivers and there's no requirement for firms to keep track of who is behind the wheel, Jones said.

Starting in 2008, all taxis will have to be equipped with cameras, which will make it clear who was driving, she said.

Barry Lazecky was working at the Bulk Barn when he saw the cab driver nudge the couple's car hard -- once, not twice -- and screamed at them to get out of his way.

The 23-year-old was glad to see someone putting a stop to the public peeing.

"He was doing his business on our wall. It's pretty gross," Lazecky says. "It's a mall. There are public washrooms everywhere."