More than 200 campaigners including Muslim leaders and trade unionists took part in the protest.
The demonstration came as Ed Miliband explained his desire for a more civilised political debate after the week-long row over the newspaper's attack on his father.
The Labour leader said Mr Cameron wanted the best for the country, but that the Prime Minister's policies were "profoundly misguided" and his actions showed he favoured the interests of the rich.
"I would never say about David Cameron that he hates Britain," Mr Miliband said on the radio in a direct reference to a Daily Mail headline that sparked the dispute.
"I would never say about David Cameron that he doesn't want the best for this country.
"Of course he wants the best for this country, so what the Mail said about my dad I would never say about David Cameron. What I would say is that I think his policies are profoundly misguided and I don't think it's true that he's leaving nobody behind."
Pressed on if he could say the Tory leader was "a good man", he said: "By his deeds he stands up for the privileged few in this country. You have to judge people by their deeds and not their words."
The Daily Mail printed an article about the Opposition leader's late father Ralph Miliband - a noted Marxist academic - under the headline: "The man who hated Britain".
Mr Miliband said the attack on his father, and subsequent gate-crashing of a private memorial service for his uncle by sister title the Mail on Sunday, were symptomatic of the culture at the titles.
Viscount Rothermere, chairman of the company which owns the newspapers, has apologised after a Mail on Sunday reporter turned up uninvited to an event commemorating Mr Miliband's uncle. MoS editor Geordie Greig also apologised and said that two journalists on his paper had been suspended pending a full investigation into what he said was "a terrible lapse of judgment".