Rupert Murdoch was attacked by a man with what appeared to be a plate of shaving foam during his appearance before MPs.
Mr Murdoch's wife Wendi and his son James jumped to his defence as the attack was launched as the final questions were being asked by MPs. The hearing resumed ten minutes after the attack with Mr Murdoch now wearing shirt sleeves but apparently unharmed.
Eyewitnesses said a member of the audience sat at the back of the room stood up and walked around to the front where Mr Murdoch was giving evidence and threw what appeared to be a paper plate covered in shaving foam at him.
As the protester was being taken from the room, Mr Murdoch's wife threw the empty paper plate at him. The session was then suspended.
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As the man was being led away in handcuffs escorted by a single police officer, he refused to give his name, saying: "As Mr Murdoch himself said, I'm afraid I cannot comment on an ongoing police investigation."
His shirt and hair was covered in what appeared to be white shaving foam.
Shortly after the foam attack, police were seen leading someone through the glass lobby of Portcullis House towards the underpass which leads to the Houses of Parliament.
An unmarked police car with flashing blue lights was seen arriving at the main entrance to the Palace of Westminster.
The alleged perpetrator was named on Twitter as Jonnie Marbles.
Marbles, who describes himself as an activist and comedian, wrote on the website just before the incident: "It is a far better thing that I do now than I have ever done before #splat."