Sunday Mirror editor Tina Weaver personally authorised hacking and blagging, political blogger Paul Staines told the inquiry into press standards on Wednesday.
Staines, who blogs as Guido Fawkes, told the Leveson Inquiry he had heard the claims from two journalists.
The blogger made the comments as part of questioning into why he was not prepared to join any regulatory body.
"Tina Weaver, somebody who two journalists have told me has personally authorised and told them to hack, blag and do all that kind of stuff, sits on not just the PCC, but on the ethics committee, the editorial standards committee.
"She knows all the bad things that have gone on under her rule. It's ridiculous."
Staines said Lord Hunt of Wirral, chairman of the Press Complaints Commission (PCC), had been trying to woo him to join a kitemark system but he did not think that was "a road" he would go down.
Asked why not, he said: "If I joined any regulatory body I would end up in a system where I am going to have to self-censor and I don't want to do that.
"I also don't want to have an editorial product that is politically correct and I don't want to have to adhere to standards that Harriet Harman would adhere to.
"I don't think there are many publishers around now, not even Private Eye, who are still politically incorrect in the way that we are."
Ms Weaver has previously told the inquiry she was not aware of phone hacking at her newspaper but there was no guarantee that it had not occurred.
She was asked about a BBC article which claimed there was routine phone hacking in the newsroom of the Sunday Mirror.
She said her organisation was "not happy" about the story which contained "anonymous allegations from seven years ago".
Counsel for the inquiry David Barr asked her if it was her position that there was "no guarantee" that phone hacking had not occurred at the newspaper.
She replied: "That is correct."