Rupert Murdoch's News Corporation has announced that it is dropping its planned bid to take full ownership of satellite broadcaster BSkyB.
It follows a scandal over phone hacking at News Corp's UK newspaper group.
News Corp deputy chairman Chase Carey said the bid had become "too difficult to progress in this climate".
The move came just before MPs debated a motion supported by all major parties calling on Mr Murdoch to scrap the bid. The motion was approved without a vote.
The scandal has already led to the closure of the UK's biggest-selling newspaper, the News of the World.
On Friday, Prime Minister David Cameron announced details of a public inquiry into phone hacking and media regulation.
"We believed that the proposed acquisition of BSkyB by News Corporation would benefit both companies, but it has become clear that it is too difficult to progress in this climate," said News Corp deputy chairman and president Chase Carey in a statement.
"News Corporation remains a committed long-term shareholder in BSkyB. We are proud of the success it has achieved and our contribution to it."
BSkyB's share price briefly dropped following the announcement, taking it down 4% for the day, before recovering to close 2% up.
The company's share price has fallen some 20% since peaking at 850p earlier this month, and is now trading at a level not seen since News Corp first announced its bid plans in June last year.
Following News Corp's announcement, BSkyB chief executive Jeremy Darroch said: "We remain very confident in the broadly based growth opportunity for BSkyB."
Shares in News Corp rose 3.8% in New York.
A spokesman for Mr Cameron welcomed the news: "As the prime minister has said, the business should focus on clearing up the mess and getting its own house in order."
The Labour leader, Ed Miliband, called it "a victory for people up and down this country who have been appalled by the revelations of the phone hacking scandal and the failure of News International to take responsibility".
Liberal Democrat deputy leader Simon Hughes said that "the sun is now setting on the Murdoch empire".
The BBC's business editor Robert Peston said: "It's a huge humiliation. This was [News Corp's] biggest investment plan of the moment. It was one of the biggest investments they've ever wanted to make.
"It is an extraordinary reversal of corporate fortune... And questions will now be asked whether this is the full extent of the damage to the empire."
News Corp already owns 39% of BSkyB, but may be compelled to give up even this minority stake if it is deemed not to be "fit and proper" by regulator Ofcom following the conclusion of current police investigations.
Robert Peston added there had been "a lot of speculation" that Mr Murdoch might now want to sell his UK newspapers, but the current state of the industry made them less attractive to potential buyers.
"The question is, who is going to pay him the price that they are worth? He will not want to sell those papers at a loss."
Business Secretary Vince Cable said it would be "very difficult" to imagine the BSkyB bid being resurrected at a later date.
Mr Cable, who was secretly recorded last year saying he had "declared war" on Rupert Murdoch, had been in charge of overseeing the bid, but was replaced by Culture Secretary Jeremy Hunt.
Mr Cameron has asked Lord Justice Leveson to oversee a public inquiry into the News of the World scandal and media regulation.
In a statement to the Commons, he said the inquiry would begin as "quickly as possible" and would be in two parts - an investigation of wrongdoing in the press and the police, and a review of regulation in the press.
The judge will have powers to call media proprietors, editors and politicians to give evidence under oath, the PM said.
Mr Cameron said those who sanctioned wrongdoing should have no further role in running a media company in the UK.
He said Lord Justice Leveson, assisted by a panel of senior independent figures, would make recommendations for a better way of regulating the press which "supports their freedom, plurality and independence from government but which also demands the highest ethical and professional standards".
He will also make recommendations about the future conduct of relations between politicians and the press.
Mr Cameron told MPs he would require all ministers and civil servants to record meetings with senior editors and media executives to help make the UK government "one of the most open in the world".
Mr Miliband welcomed the proposal, arguing it must be imposed retrospectively, so that he and Mr Cameron publish all details of meetings with media executives dating back to the last general election.
The prime minister was previously criticised for meeting Rupert Murdoch, head of News Corporation, in Downing Street soon after the election, because Mr Murdoch did not walk through the front door.
Newspapers which did not support the government ran stories of "secret meetings".
Earlier at prime minister's questions, Mr Cameron said a "firestorm" was engulfing parts of the media and police, and those who had committed offences must be prosecuted.
Mr Miliband said it was an insult to the family of murdered schoolgirl Milly Dowler, whose phone was allegedly hacked, that Rebekah Brooks was still News International's chief executive.
Mr Cameron responded: "She was right to resign, that resignation should have been accepted. There needs to be root and branch change at this entire organisation.
"What has happened at this company is disgraceful - it's got to be addressed at every level."
In other developments:
- Former Prime Minister Gordon Brown told the House of Commons that lawbreaking has taken place "on an industrial scale"
- News International's legal manager Tom Crone, who primarily worked at the News of the World and on the Sun, has left the company
- The Sun undefined . It has released a video of the man it says was the source - the man's face is not revealed and his voice is disguised to protect his identity
- The prime minister met the parents of Milly Dowler, after which they welcomed news of the phone hacking inquiry
- The Australian arm of Mr Murdoch's media empire is to investigate all payments made to contributors since 2008
- In the US, undefined and whether journalists working for News Corp had broken US law
- Shares in News Corp have fallen 14% since 4 July, wiping about $5bn off the company's value
Meanwhile, Labour's communications chief Tom Baldwin is facing renewed questions over claims he handled private information which was gained illegally during his years at the Times newspaper, another News International publication.
The former Conservative deputy chairman Lord Ashcroft makes the allegations in a blog posting on ConservativeHome, which he owns. Mr Baldwin has not responded to the claims.