Demonstrators against the cuts include public sector workers, pensioners and students [AFP]

Tens of thousands of people have rallied in London, the British capital, in opposition to public spending cuts introduced by the country's coalition government.

There were outbreaks of violence amid Saturday's demonstration as several hundred masked protesters clashed with police and rampaged down London's main shopping district.

About 4,500 police officers were deployed ahead of the protest.

Away from the main protest, a group of black-clad protesters threw paint bombs at shops and banks on the main shopping streets of Oxford Street and New Bond Street.

Police said that some protesters also threw paint bombs and light bulbs filled with ammonia at officers during the demonstration.

Several banks were attacked and the Fortnum and Mason department store was briefly occupied.

UK Uncut, a group that campaigns against government cuts and corporate tax avoidance, claimed it was behind the occupation.

Five policemen were injured during the protests. Police arrested 157 people.

'Serious message'

But the main demonstration, billed as the "March for the Alternative", went peacefully with families and their children among the protesters.

Steel bands, choirs and dancers also joined the march, giving a carnival atmosphere to the demonstration.

Tim Friend, Al Jazeera's correspondent at the march, said: "It's all good fun for many people here but there is a serious message as well, which the government will be watching very carefully.

"There are 'unsung heroes' here, from communities across Britain who have come down to London.

"The closure of their projects [due to cuts] for their local communities might not get much publicity, but for the people who use those services it will be absolutely devastating."

Many protesters carried banners reading "Don't Break Britain", "No to Cuts" and "Defend Our Public Services", while others blew vuvuzelas, the plastic trumpets made famous during the South African football World Cup.

Organisers had claimed earlier that the demonstration could be the biggest rally in the capital since mass protests against the invasion of Iraq in 2003.

Political protest

The demonstrations were called over cuts to public spending, rising unemployment, tax rises and pension reforms imposed by the government after it came to power in May.

The Conservative-Liberal Democrat coalition has announced plans for cuts worth £81bn ($131bn) over five years in order to slash a record public deficit that the party's blames on the previous Labour administration.

The cuts involve most government departments, with the loss of 300,000 public service jobs and pay freezes for civil servants.

The Liberal Democrats have faced public criticism for supporting the austerity measures, especially the hike in university fees which it had opposed before it came to power.

Ed Miliband, the Labour leader, spoke at the rally, likening the protest to the suffragette movement in Britain and the civil rights movement in America.

"Our causes may be different but we come together to realise our voice. We stand on the shoulders of those who have marched and have struggled in the past," he told protesters gathered in London's Hyde Park.

The UK march is the latest protest against austerity measures to take place in Europe where governments are struggling to bring down record deficits following bailouts and bank nationalisations in the wake of the financial crisis.