4.59pm: Reports claim the assailant is a UK Uncut activist.
4.58pm: The BBC's Laura Kuenssberg thinks it's a bandage on the young man's face – Nick Robinson says it is shaving foam and the young man hit Rupert Murdoch with it.
4.57pm: The suspect looks like he has a substance like white paint on his face.
My colleague Jackie Ashley tells Twitter: "Wendi [Murdoch's wife] can throw quite a punch."
4.56pm: The BBC says the young man has been handcuffed. Sky showed the footage again – it seemed to be an attack from Rupert Murdoch's left.
4.55pm: A young man in a checked shirt has been detained by police.
4.54pm: Someone has just tried to attack Rupert Murdoch. His wife Wendi seemed to slap the person.
4.51pm: RM says papers should never break the law.
He was brought up by a father who was not rich, but who was a great journalist. He bought a small paper and said that he would use it to do good. He used it to expose the scandal of Gallipoli - something which aroused hostility in Britain.
Collins asks about RM's relations with politicians.
RM says he wishes they would leave him alone. The prime minister to whom he was closest was Gordon Brown, he says. He thought Brown had good values. Their wives became close. Their children played together (he has two young daughters). He is sorry that Brown has fallen out with him, but he hopes they will repair their relationship.
