Rupert Murdoch's daughter Elisabeth has warned of the threat to press freedom from "enemies within" - a remark which will be widely seen as a criticism of News International, currently caught up in the phone-hacking scandal.
In a speech to television executives, she insisted that "profit without purpose is a recipe for disaster, " explicitly contradicting her brother's speech to the Festival in 2009, in which he said he said profit was the only "reliable and perpetual guarantor of independence".
She said that one of the "biggest lessons" for NewsCorp was the need for "a rigorous set of values based on an explicit statement of purpose"
Speaking at the annual industry get-together, she said News Corp was "currently asking itself some very significant and difficult questions about how some behaviours fell so short of its values".
She criticised comments made by her brother in 2009 in which he lambasted the BBC and accused the corporation of a "land grab".
Ms Murdoch, quoted from her brother's lecture in which he said profit was the only "reliable and perpetual guarantor of independence".
But she told her audience he left something out, adding: "The reason his statement sat so uncomfortably is that profit without purpose is a recipe for disaster."
She said industry and "global society" need to "reject the idea that money is the only effective measure of all things or that the free market is the only sorting mechanism".
She added: "Let's see what the Leveson Inquiry recommends but, when there has been such an unsettling dearth of integrity across so many of our institutions, it is very difficult to argue for the right outcome - which must be the fierce protection of a free Press and light-touch media regulation. Sadly, the greatest threats to our free society are too often from enemies within."
She also quoted another former MacTaggart speaker, Dennis Potter, who said television should "make hearts pound".
The playwright famously used his lecture to demand that her father be put on trial and even named his cancer Rupert after him.
Elisabeth Murdoch founded production company Shine which is responsible for shows such as MasterChef and Merlin
Ms Murdoch took the time to praise the BBC and the "vision and leadership" of outgoing Director-General Mark Thompson and described herself "on the record" as "a current supporter of the BBC's universal licence fee".
But she warned Mr Thompson's successor, George Entwistle, that he would have to demonstrate how "efficiently" the corporation spent its money.
The speech ended with a hymn of praise to her father, telling how he "had the vision, the will and the sense of purpose to challenge the old world order on behalf of 'the people'".
Her often deeply personal remarks included a reference to the family's position as "permanent outsiders and constant nomads" but in "pursuit of a greater good - a belief in better".
Previous speakers asked to give the prestigious lecture at the event, formally known as the MediaGuardian Edinburgh International Television Festival, include Jeremy Paxman and Google boss Dr Eric Schmidt.