The demonstration dubbed “A Future That Works” was organized by Trade Union Congress (TUC) and attracted hundreds of thousands of people across Britain, local media reported.
The anti-greed protesters called on the government to adopt an alternative economic strategy that puts jobs and growth first.
The TUC chief, Brendan Barber said the message of the Saturday’s protest was that “austerity is simply failing”.
“The government is making life desperately hard for millions of people because of pay cuts for workers, while the rich are given tax cuts,” he said.
Unions, anti-war campaigners, left-wing leaders, community groups and other activists joined the demonstration against reductions to public sector spending in London’s streets.
The cuts are claimed to be aimed at reining in the UK’s huge debt, which stands at more than one trillion pounds. Britain borrowed 13 billion pounds in September alone.
The UK government was also accused of leaning towards rich people, when earlier this year, it reduced income taxes for the country’s wealthiest citizens.
The coalition is said to be cutting taxes for millionaires and raising them for everyone else in the country.
“It is one rule for those at the top and one rule for everyone else”, said Labour Party chief Ed Miliband, who addressed the demonstrators at London’s Hyde Park.