Only three of 30 notebooks found in seven boxes of material withdrawn from News International's archives the day before the News of the World closed belonged to Rebekah Brooks, her personal assistant told the police.

Cheryl Carter, who worked for Mrs Brooks for 16 years, gave the explanation after she was arrested at dawn at her home in Billericay, Essex.

In July 2011 Mrs Carter arranged for the removal of the seven boxes logged: "All notebooks from Rebekah Brooks (nee Wade) 1995-1997" from NI's archives in Enfield.

Police claim that she was part of a conspiracy with Mrs Brooks to hide evidence from the police inquiry into phone hacking at the News of the World - which Mrs Brooks edited between 2000 and 2003.

However Mrs Carter told police in her interview that most of the approximately 30 notebooks in the boxes had been hers, rather than Mrs Brooks.

After throwing most of her own notes into her recycling box at home, she had returned the small amount of Mrs Brooks's belongings to her office at News International.

Of her boss's possessions, she said: "I noticed that there was three of Rebekah's pads [notebooks], there was one diary, there was some photographs and there were some speeches."

Asked who had originally told the archive the boxes were Rebekah Brooks's, Mrs Carter replied: "I wouldn't have said my old notebooks. I would have put them down as Rebekah's because that was my office."

She suggested that the company's archivist had called her twice in April or May 2011 to ask for her to remove the boxes because of a lack of storage space. In his interview with the police, the archivist rejected this. Nick Mays said: "I did not call Cheryl Carter to remove any boxes from Enfield."

He noted that Mrs Carter said that most of the material in the boxes was hers or that of another personal assistant, rather than Mrs Brooks's.

Given that the archivist had no interest in the content of the boxes, Detective Sergeant John Massey asked: why did she say that?

Mrs Carter replied: "I do not know. I can't answer that. I don't know."

She said that despite having a close relationship with Mrs Brooks, she was unaware she was about to resign and had no forewarning that the News of the World was about to close.

She said that Mrs Brooks had been a good boss to her, adding: "She was tough. She shouted a lot."

Three weeks after the interview, Mrs Carter had been intending to emigrate to Australia.

Asked what she would be doing there, she replied: "Well they said maybe I can have a job at the Sunday Times, Perth." The Sunday Times in Perth is owned by Rupert Murdoch.

Mrs Carter and Mrs Brooks both deny conspiracy to pervert the course of justice. The case continues.