A protester attacked media mogul Rupert Murdoch with a plate of foam in Britain's parliament on Tuesday, bringing a televised hearing on the News Corp phone-hacking scandal to a halt.
Murdoch's wife Wendi Deng, who was sitting behind her husband, slapped the assailant and police rushed to arrest him.
The 80-year-old Murdoch was unhurt and was able to resume giving testimony after a 15-minute suspension of the hearing, watched by millions who have followed the phone-hacking scandal that has engulfed Murdoch's global media empire.
Police took the attacker, whose face was smeared in foam, out of the room and placed him in handcuffs.
"It was chaos, people leaping towards the assailant, and (Murdoch's) wife leading the charge," said Andy Thompson, 40, a theatre producer from Vancouver in Canada, who was sitting three rows behind Murdoch and his son James when the attack occurred.
"Some of us were falling asleep with James Murdoch's stuttering answers and then this (happened) -- completely out of the blue," said Thompson.
Luca Morreale, who was sitting beside the attacker, said: "It happened so quick. He jumped up out of his seat and pulled what looked like a pie out of a plastic bag."
Murdoch appeared calm when the hearing resumed but had taken off a blue suit jacket that had been splashed with the foam.
Chris Bryant, an opposition Labour Party member of parliament who has been prominent in the campaign against News Corp over the phone-hacking scandal, condemned the attack.
"It's just appalling. The whole point is that we've been trying to make sure that people are held responsible properly and decently," said Bryant.
British media said the attacker appeared to be a man who identified had himself as "Jonnie Marbles" on the Twitter micro-blogging website.
"It is a far better thing that I do now than I have ever done before ... ," said his last tweet.