One of the News of the World's most senior executives had not even realised phone hacking was possible before the arrest of the paper's royal editor seven years ago, the hacking trial heard today.

Managing editor Stuart Kuttner told detectives interviewing him that he had been "shaken by the deception" of Clive Goodman, who had paid the private detective Glenn Mulcaire to intercept phone messages.

The court has previously heard that some of the News of the World biggest stories came from the interception of mobile phone messages, such as the hacking of then Home Secretary David Blunkett in 2004.

However in transcripts of his interview with police in August 2011, Mr Kuttner said he had not even known before Mr Goodman's arrest for hacking in 2006 that it was "physically possible" to hack phones. "I was quite unaware of it," he told detectives.

Asked if he had known that Mr Goodman had been working with Mulcaire, Mr Kuttner - whose responses to detectives were read out to the jury at the Old Bailey - replied: "Possibly, yes," before adding: "I don't know is the answer."

Mr Kuttner, on trial for conspiring to hack phones, told police that he was keen to help them despite his health difficulties. His solicitor told officers at Leyton police station in Essex that a heart attack and a stroke had impaired Mr Kuttner's short and long-term memory, including his ability to recall "detail."

Mr Kuttner, who was managing editor of Britain's best-selling Sunday paper until 2009, told detectives: "Look I will do my best, regardless of the heart attack and brain stem stroke…to answer your questions."

Asked where he had been in the chain of command on the News of the World, he said his role had been "sideways." "I'm not in the chain of command," he said. "The managing editor... is silent."

He had only "occasionally" taken an interest in stories and had a role in authorising payments but was not the most senior financial officer, he told the police,He explained that he had been "utterly appalled" to discover the extent of phone hacking at the News of the World. Furthermore, he was "shattered" by having to attend the police interview and answer "completely unfounded allegations."

Mr Kuttner said: "I have never knowingly bribed a policeman and I have never knowingly played a part in the bugging or hacking of any telephone and I am very shocked at what's happened today."