The shadow culture secretary, Harriet Harman, has said Rupert Murdoch owns "too many newspapers" in the UK and has called for legislative change to address this.
Harman said the forthcoming 2015 Communications Act presented an "opportunity to take action to deal with difficult, historical problems which have been left unaddressed for too long".
She added that the green paper which the government will publish by the end of the year setting out the scope for the act needs to examine ways of curbing Murdoch's power.
"The accumulation of too much power led to a sense of invincibility and impunity," Harman said, speaking at a Westminster Media Forum event about the upcoming communications legislation in Whitehall on Tuesday.
"Murdoch owns too many newspapers and had it not been for the phone-hacking scandal the government would have waved through his bid to take control of the whole of BSkyB. Both Ofcom and Leveson are looking at ownership. It is clear that there needs to be change," the Labour MP added.
"The malpractice and illegality which has been exposed by the Leveson inquiry was never just 'one rogue reporter' or a few bent policemen. It is a symptom of an underlying structural problem."
Harman was also candid about the failings of the Labour government she was part of when it came to courting Murdoch.
"People have also said: 'But you were in government for 13 years – why didn't you do something about it? You were too close weren't you?'," she told delegates.
"When we were in government, it was the case that many senior figures did become too close to News International and Murdoch."
However, Harman said this was a direct result of the mauling the Labour party received during the 1992 general election, which damaged its performance at the polls.
"The answer to that lies in what happened before 1992. We put in our 1992 manifesto what we believed was necessary: that we should 'establish an urgent inquiry' by the Monopolies and Mergers Commission into media ownership, and – if the press failed to deal with abuses of individuals' privacy – to implement the statutory protections recommended by the Calcutt report," she added.
"Because we were committed to tackling media monopoly and introducing a robust press complaints system, the Murdoch press was determined to stop us getting into government and not a day went by without on every issue, his papers battering us.
"So as we approached 1997, we – in Tony Blair's words in his famous 'feral beasts' speech – turned to 'courting, assuaging and persuading the media... after 18 years of opposition and the, at times, ferocious hostility of parts of the media, it was hard to see any alternative'."
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