Hislop is appearing today before the Leveson inquiry into media standards and phone hacking.
He said: “If the prime minister appoints the former News of the World editor as his communications director, News International will think ‘We are top of the pile, nothing can stop us’.”
But he also said new laws weren’t the answer – arguing that phone hacking, paying police officers and being in contempt of court all go against existing laws.
The Have I Got News for You panelist said the inquiry should focus on why the laws were not properly enforced.
Tom Mockridge, who followed Rebekah Brooks as News International’s chief executive, is also being questioned.
Mockridge said he was “completely confident” that News International’s use of search agents had ended and that editors had been instructed not to use private investigators.
He also said the culture of News International was slowly evolving.
He said: “It might be overambitious to say the culture entirely has changed in six months, but there has been a change of policy … and individuals are rigorously applying policy.”
Guardian editor Alan Rusbridger, The Times’ James Harding and Sunday Times’ John Witherow will give evidence later today.
On Monday the editors of the Daily Mirror and Sunday Mirror admitted that phone hacking may have happened at their papers too.