Trinity Mirror, the owner of Daily Mirror and Sunday Mirror, has formally apologised to all the victims of phone hacking.
The publisher printed the apology in the Daily Mirror after it admitted voicemails left on certain people's phones were "unlawfully accessed".
Singer Cilla Black, former England football team coach Sven-Goran Eriksson and actress Shobna Gulati are some of the people who had have their phones hacked by Trinity Mirror.
The Daily Mirror has had to settle claims with a number of people after they were the victims of "an unacceptable intrusion" into private lives.
The published apology said: "Some years ago voice-mails left on certain people's phones were unlawfully accessed. And in many cases the information obtained was used in stories in our national newspapers.
"Such behaviour represented an unwarranted and unacceptable intrusion into people's private lives.
"It was unlawful and should never have happened, and fell far below the standards our readers expect and deserve.
"We are taking this opportunity to give every victim a sincere and unreserved apology for what happened."
Last November, Graham Johnson, the Sunday Mirror's former investigations editor, became the first Trinity Mirror reporter to admit phone hacking.
He pleaded guilty to hacking a phone to investigate whether a well-known soap star was having an affair with a gangster in 2001.
Until then, all phone hacking claims centred around the News of the World, with the scandal forcing the closure of the Sunday paper.
Trinity Mirror said intercepting voicemail no longer takes places at any of its papers.
The company added: "We recognise that our actions will have caused them distress for which we are truly sorry.
"Our newspapers have a long and proud history of holding those in power to account. As such, it is only right we are held to account ourselves.
"Such behaviour has long since been banished from Trinity Mirror's business and we are committed to ensuring it will not happen again."