Politicians from the Prime Minister down are scared of standing up to “assassins” in the media, Black Country MP Tom Watson has claimed.

The West Bromwich East MP launched a remarkable attack on “barons of the media” during a passionate speech in the House of Commons.

He claimed: “They have no predators. They are untouchable. They laugh at the law. They sneer at parliament. They have the power to hurt us, and they do, with gusto and precision, with joy and criminality.”

Mr Watson (Lab West Bromwich East) said media mogul Rupert Murdoch, publisher of The Sun, The Times and the News of the World, should be summoned to Parliament to explain himself to MPs.

He was speaking as the Commons referred the News of the World phone-hacking row to the parliamentary sleaze watchdog for further investigation.

A motion authorising the Standards and Privileges Committee to launch a probe was nodded through the Commons without a formal vote.

The row centres on the period when Downing Street communications chief Andy Coulson edited the Sunday tabloid newspaper.

Mr Coulson has always denied any knowledge of the illegal eavesdropping at the News of the World, for which ex-royal editor Clive Goodman and a private detective were jailed in 2007.

The News International-owned paper insists that the Goodman case was isolated and there was no widespread culture of wrong-doing among staff.

Referring to News International Chief Executive Rebekah Brooks, Mr Watson told the Commons: “The truth is that we all of us in this House in our own way are scared of the Rebekah Brooks of this world.

“If you fear passing this resolution, think of this; it’s almost laughable. Here we sit in parliament, the central institution of our sacred democracy, between us, some of the most powerful people in the land, and we are scared of the powers she wields without a jot of responsibility or accountability.

“They, the barons of the media, with their red-topped assassins, are the biggest beasts in the modern jungle.

“They have no predators. They are untouchable. They laugh at the law. They sneer at parliament. They have the power to hurt us, and they do, with gusto and precision, with joy and criminality.

“Prime Ministers [cower] before them. And that is how they like it. That, indeed, has become how they insist upon it.

“And we are powerless in the face of them. And we are afraid. And if we oppose this resolution, it is our shame.

“That is the tawdry secret that dare not speak its name.

“The most powerful people in the land, Prime Ministers, Ministers and MPs of every party, are guilty in their own way of perpetuating a media culture that allows the characters of the decent to be traduced out of casual malice.

"For money, for sport, for any reason they like, and if we reject this resolution we will be guilty of letting it happen.

“We allow it because we allow narrow party advantage to dominate our thinking above the long term health of our democracy. And yet, Mr Deputy Speaker, I sense we are at the beginning of the endgame.

“Things will get better because in many senses they couldn’t get worse.

“The little guys, the reporters on the ground who joined the newspapers to seek truth, have ended up working in a living hell.

“But if we want to, we have the power in this House to change that. We can make a start by getting to the bottom of the phone hacking scandal.”

The News of the World’s sister paper, The Sun, last October agreed to pay “substantial” damages to Mr Watson after falsely accusing him of being part of a smear operation aimed at Labour’s opponents.