Counter terrorism police have searched an east London property whilst investigating attacks at a London tube station.
Officers responded to reports of multiple stabbings at Leytonsone tube station on Saturday evening.
Video footage shows officers using a taser on the 29-year-old suspect before arresting him on suspicion of attempted murder. The suspect is currently being held at an east London police station.
Commander Richard Walton, who leads the Met's Counter Terrorism Command,said: "I would like to thank everyone who has so far provided information to officers and to the Anti-Terrorist Hotline following this unprovoked violent knife attack last evening at Leytonstone Underground Station."
He urged witnesses to come forward if they have any footage of the incident on their mobile phones.
Mr Walton said: "I am aware that there were a number of members of the public in the underground station who filmed the suspect on their mobile phones during and after the attack and I would urge them to come forward and speak to us and share with us the filming that they carried out."
Detective Superintendent Jacqueline Sebire has praised officers from Waltham Forest borough for their quick response.
A 56-year-old man sustained serious knife injuries and was given first aid by officers at the scene. He was later taken to an east London hospital where he remains in a stable condition; his injuries are not believed to be life-threatening.