Royal Galipeau stands the House of Commons after Question Period, Wednesday May 16, 2007. (CP/Fred Chartrand)

An ugly brawl broke out yesterday in the Commons, where a Liberal MP claims he was physically accosted and threatened by a Conservative who "flipped out."

Ottawa MP David McGuinty accused Tory MP Royal Galipeau of storming across the floor and unleashing a tirade of insults. He called the conduct the worst he has seen in his three years on the Hill.

"The member was clearly out of control, using unparliamentary language and in a threatening fashion grabbed my left shoulder and only left my side when several of my colleagues urged him to stop and to leave, but he would not," McGuinty said.

"He was really completely out of control, raising his voice, flailing his arms, gesticulating in a threatening fashion and making wild accusations."

McGuinty, who was posing a question about language rights and the court challenges program at the time, has asked the House Speaker to investigate.

Galipeau, who is also from Ottawa, is deputy Speaker and charged with keeping peace and decorum in the Commons.

He admits he lost his cool, but denies he behaved in an intimidating manner.

"Yes, I was pretty upset, but I was only upset because I was surprised," he said. "How can I be threatening to (McGuinty)? He's bigger than I am, he's stronger than I am, he's younger than I am."

It said it was continuing its lawsuit against blockade organizer Shawn Brant and other individuals.