The Sunday Mirror carried out phone hacking "on a fairly grand scale", a former reporter at the newspaper told a trial at the Old Bailey yesterday.
Dan Evans, 38, said phone hacking went on for several years at the tabloid, where he learned how to intercept voicemails during a "secret" meeting with another journalist.
Evans, who also worked at the News of the World, pleaded guilty last year to phone hacking at the Sunday Mirror.
He is the first person to plead guilty to phone hacking at any newspaper other than the News International title, which was closed three years ago. The jury was told Evans admitted hacking at both Sunday tabloids, as well as conspiracy to commit misconduct in a public office and making a false statement.
The court also heard he entered into a written agreement with the Crown Prosecution Service last year, as a result of which he was appearing as a prosecution witness.