Mr. Cameron closed the annual Conservative Party conference with a speech mocking “Red Ed and his Blue Peter economy,” a reference to a children’s television program and Mr. Miliband’s plans to freeze energy prices. But it was a far cry from implying that Mr. Miliband was on a secret mission from his father to undermine the country and move it toward Stalinism, as the Daily Mail broadly suggested.

Unfortunately for Mr. Cameron, who has been trying to energize his party for the general election due in 18 months, the newspaper and its editor, Paul Dacre, who are putative allies of the Conservatives, gave Mr. Miliband days of publicity that took attention away from the Cameron message.
The attack allowed Mr. Miliband to mount an emotional defense of his father, a Jewish immigrant who enlisted in the Royal Navy to fight the Nazis; he later became a respected university professor and left-wing theorist, and died in 1994.
Even Mr. Cameron acknowledged some sympathy with Mr. Miliband and his anguished reaction to the attack. “If anyone had a go at my father, I would want to respond vigorously,” he said.
The deputy prime minister, Nick Clegg, of the Liberal Democrats, chose a sporting metaphor to support Mr. Miliband, writing on Twitter: “Politics should be about playing the ball, not the man, certainly not the man’s family.”
Mr. Cameron had few new policies to announce on Wednesday. But as expected, his tone was decidedly to the right, intended to rally his party and attract voters who may be leaning toward the United Kingdom Independence Party, which is anti-Europe and anti-immigrant. In his remarks, Mr. Cameron emphasized his government’s efforts to limit immigration and toughen welfare requirements, and hinted that more was to come.
“This is what we want to see: everyone under 25 earning or learning,” he said, suggesting that if the Conservatives win another term, young Britons might be denied welfare payments if they refused to take up offers of work, training or education. This week, the chancellor of the Exchequer, George Osborne, announced plans to make the long-term unemployed do community work to continue receiving benefits.
At the conference in Manchester, Mr. Cameron said “the land of despair is Labour,” with its “1970s-style socialism,” while “the land of hope is Tory.” He said the government would continue to cut spending and debt. “To abandon deficit reduction now would throw away all the progress we have made,” he said.
Acknowledging that for many Britons, “these past few years have been a real struggle,” he said that “the struggle will only be worth it if we, as a country, finish the job we started.”
Mr. Cameron painted Mr. Miliband as a throwback to an outdated Socialism that the party had seemed to abandon under Tony Blair. But Mr. Miliband won the sympathy vote after the Daily Mail attack, even from a former Conservative cabinet minister, Michael Heseltine, who told the BBC that the newspaper was “carrying politics to an extent that is just demeaning, frankly.”
A column by Geoffrey Levy in Saturday’s Daily Mail cited a diary entry Ralph Miliband made at 17 during World War II, in which he despaired at the complacency of the British and their mistrust of foreigners. He wrote that they were “perhaps the most nationalist people in the world,” adding that “you sometimes want them almost to lose, to show them how things are.”
Britain nearly did lose the war, but the elder Mr. Miliband did his part, volunteering in the navy. His son wrote an anguished reply to the column in the Daily Mail on Tuesday, defending his father and saying, “Fierce debate about politics does not justify character assassination of my father.” He added, “To ignore his service and work in Britain and build an entire case about him hating our country on an adolescent diary entry is, of course, absurd.”
The rift comes at a delicate time, with discussions scheduled for next week on proposals to tighten regulation of the press after an inquiry into a scandal over phone-tapping by reporters, most notably those from Rupert Murdoch’s news media empire.
Though the main political parties have agreed on a plan, Britain’s newspapers have put forward their own blueprint, and the fate of that initiative may be decided next week. Mr. Miliband criticized Mr. Murdoch during the phone-tapping saga, and now has been pushed into a confrontation with The Daily Mail.
Education Minister Michael Gove, a former journalist, gave a more equivocal view on Wednesday. “While we respect Ed Miliband’s right to stick up for his father — and I don’t think any of us would want to be in anything other than the position he is in of standing by our family — it is also the case that we shouldn’t allow ourselves to think that politicians should have a right to regulate or second-guess what happens in the papers,” he said.