A 38-year-old man arrested under the Terrorism Act was released without charge today, police said.
The man, who has not been named, was detained by officers in Hawkinge, near Folkestone, Kent, on Monday morning.
Kent Police were due to seek extra time to detain the man at a court hearing this evening but announced that he had been freed without charge this afternoon.
The man had been questioned at a police station in Kent on suspicion of being engaged in the commission, preparation or instigation of an act of terrorism.
There is no suggestion that the arrest was linked to last week's Channel Tunnel fire or recent investigations in the North of England into an alleged threat to kill Prime Minister Gordon Brown.
Scotland Yard said the Metropolitan Police Counter Terrorism Command was not involved in the inquiry.
Part of the police inquiries have focused this week on a house in Curlew Place, Hawkinge, a quiet cul-de-sac on a modern housing estate.
Neighbours of the man who was held said they did not know him well but believed he was Turkish and lived in the detached house with his family.Reuse content