Ed Miliband tried to muster residual anger over MPs' expenses and the banking crash as he sought to accelerate the momentum of the phone-hacking scandal in a speech later.
The Labour leader told an audience at KPMG's headquarters in the City that the three scandals are united by a "responsibility deficit" which has developed in British society.
He called for a "new culture, rules and structure" which helps people become more responsible, regardless of their profession.
"Down the ages, it is large concentrations of power that lead to abuses of power and neglect of responsibility," Mr Miliband said.
"In the banks, they were too big to fail. And the same is true in our media."
He argued that Rupert Murdoch's control of nearly 40% of the newspaper market and 80% of the pay TV market through Sky are unhealthy for Britain.
News International had sought to gain 100% control of BSkyB but abandoned the £10 billion takeover bid last week. It currently owns 39% of the broadcaster.
"It is not healthy for consumers, who see choice constrained," Mr Miliband added.
"It is not healthy for our democracy, where we see too much power in one set of hands.
"It is not healthy for a country that believes in responsibility all the way to the top of society."
Mr Miliband said it was important for political leaders to "find the courage to challenge other areas where concentrations of power damage our country".
He pointed out that six energy companies control 99.9% of the consumer market. "This cannot be right," Mr Miliband said, "and we must take action to open up the market over the coming months".
politics.co.uk asked the Labour leader whether he thought the phone-hacking scandal had opened up an opportunity for him to tackle the 'establishment'.
He did not use the word in his speech but said he was prepared to confront "parts of it".
"I'm very struck because people talk in a lot in our society and rightly so about the responsibility of people on benefits," he told politics.co.uk.
"There's absolutely no way we can get the culture we need at the bottom of society from those on benefits if we see those in power and those in powerful positions abusing their positions of trust.
"The powerful have to show some of the same responsibility that they're demanding of the powerless."
The leader of the opposition's comments came a day after he told the Observer newspaper that the concentration of power enjoyed by Mr Murdoch is "frankly quite dangerous".
His strong stance against News International has seen him improve his position among voters. Twenty-seven per cent of respondents to a survey conducted by ComRes for the Sunday Mirror said they thought he was doing a good job, compared to 18% last month.