Dramatic video shows UK police Taser and arrest a suspect following a mass stabbing attack on a train that left 11 people wounded, two of them critically.

UK police on Sunday arrested an Ethiopian asylum seeker and convicted sex offender, whose crimes had sparked anti-immigration protests, after he was accidentally released from prison in an embarrassing blunder by officials.

UK police ruled out terrorism in relation to Saturday’s mass stabbing attack on a train in central England, as two people remain in a life-threatening condition in hospital.

At first, police used the code word "Plato" — a term in the UK that signals a possible "marauding terror attack."