Cressida Dick says the public should be 'alert but not alarmed', as more police are deployed on the streets of the capital, after Friday's terror attack on the London Underground. During a walkabout in Westminster on Saturday, the Metropolitan Police Commissioner described the investigation into Friday's attack as 'fast moving' and said 'considerable progress' has been made. It follows the arrest of a suspect in Dover by Kent Police earlier today. Report by Carrf. Like us on Facebook at http://www.facebook.com/itn and follow us on Twitter at http://twitter.com/itn
