Police want to speak to an aggressive train passenger who threatened five teenagers with a knife on a central line train.
Detectives from British Transport Police (BTP) are appealing for information after the incident, which took place around 8.30pm on Friday, 20 December 2013.
Detective Constable Carl Wayte, the investigating officer, said: "A man was attacking another passenger on an eastbound Central line train as it travelled between Loughton and Theydon Bois London Underground...
