Police said they were treating the stabbing at Leytonstone station as a terrorist incident.
One man sustained serious injuries not considered to be life-threatening, police said. Two others suffered minor injuries.
The suspect was taken to a London police station.
Police said they were called just after 7 p.m. to reports of a number of people stabbed at the station and a man threatening others with a knife.
Commander Richard Walton, who leads the Met's Counter Terrorism Command, said: 'We are treating this as a terrorist incident.'
'I would urge the public to remain calm, but alert and vigilant. The threat from terrorism remains at severe, which means that a terrorist attack is highly likely.' "
God I love Britain.
