Violence has broken out on the streets of central London, England has tens of thousands of people have demonstrated to express their opposition to drastic spending cuts by the British government.

Organizers claim that more than a quarter of a million people have appeared at the march, far more than expected.

It is believed to be the largest union-organized event in Britain in more than two decades years; and the biggest overall public march in the nation since the invasion of Iraq in March 2003.

The Conservative-Liberal Democrat coalition led by Prime Minister David Cameron plans spending cuts of about $131-billion over the next five years, including slashing about 300,000 public sector jobs.

Protesters marched from Victoria Embankment to Hyde Park, where Brendan Barber, the general secretary of the Trades Union Congress (TUC), which organized the march, spoke.

We are here to send a message to the government that we are strong and united, he said.

We will fight the savage cuts and we will not let them destroy peoples' services, jobs and lives.

Ed Miliband, the leader of the opposition Labour Party addressed large crowds in Hyde Park.

The Tories said I should not come and speak today,” he said.

“But I am proud to stand with you. There is an alternative.

Michael Fallon, deputy chairman of the Conservative party, defended the spending cuts and attacked the opposition’s lack of a credible alternative plan:

Ed Miliband can't attend a march for an alternative rally when he's done nothing to set out an alternative,” he said.

If he and the unions that elected him oppose the cuts, they need to set out a credible alternative. Doing nothing is not an option. We have set out a credible plan backed by the IMF, OECD and every major business body in Britain to put the public finances back on track.”

Many protesters held up banners which read: Don't Break Britain, No to Cuts and Defend Our Public Services,

The noise in Whitehall was deafening as thousands of protesters banged drums, blew whistles and shouted anti-cut slogans, slowly making their way towards Trafalgar Square,” a BBC reporter said.

The crowds were booing as they went past Number 10, but the demonstration was good-natured and friendly. There are hundreds of trade union banners, but we have also spoken to public sector workers who have come to make their voices heard.

One protester told BBC: I think it's wrong the way we are hitting the poor. I'm not so much worried about myself but the customers I deal with are vulnerable and I'm worried about them and I'm worried about the kids of this country.

While most marchers were peaceful, according to BBC correspondents a small group of protesters attacked banks and stores in the West End; while some scuffled with the police. At least one person has been arrested on suspicion of committing damage to property.

The London Metropolitan Police indicated that the troublemakers were not affiliated with the TUC marchers.

According to eyewitnesses, the crowds included union members, students, older folk and families.

Another rally participant said to BBC: The size and scale of [the rally], and the range of people here, is great. There are a lot of trade unionists here, but it's not just the usual suspects.

The government has insisted that spending cuts are necessary to bring the deficit down and restore fiscal sanity.

Len McCluskey, general secretary of the Unite union, responded to the government’s assertions: Our alternative is to concentrate on economic growth through tax fairness so, for example, if the government was brave enough, it would tackle the tax avoidance that robs the British taxpayer of a minimum of £25-billion a year.

At least one high government official sympathized with the protesters.

Education Secretary Michael Gove said: The difficulty that we have as the government inheriting a terrible economic mess is that we have to take steps to bring the public finances back into balance.”

Barber has warned that the coalition government faces a crushing defeat in the next general election in May.

The thousands coming to London from across the country will be speaking for their communities when they call for a plan B that saves vital services, gets the jobless back to work and tackles the deficit through growth and fair tax, he declared.

No part of our public realm is to be protected. Don't believe it when ministers say that the [National Health Service] is safe in their hands. With over 50,000 job cuts already in the pipeline – nurses, doctors… midwives – in the name of so-called efficiency savings of £20-billion, the NHS as we know it, is already in intensive care. With David Cameron talking about selling it off to any willing provider out to make a profit, the NHS is facing the gravest threat in its history. Today let us say to him: we will not let you destroy what has taken generations to build. Let's be brutally clear about these brutal cuts. They're going to cost jobs on a huge scale – adding to the misery of the 2.5-million people already on the dole. They’re going to hammer crucial services that bind our communities together, and they're going to hit the poorest and the most vulnerable hardest. Anyone who tells you different is a barefaced liar.”

Barber further added: The Government claims there is no alternative, but there is. Let's keep people in work and get our economy growing. Let's get tax revenues flowing and tackle the tax cheats, and let's have a Robin Hood Tax on the banks, so they pay us back for the mess they caused.

Matt Wrack, general secretary of the Fire Brigades Union, said: Cameron… [has] launched a war on working people and today's demonstration is the start of the fightback.They expect us to suffer tax increases, pay cuts, unemployment and devastation of our pensions to pay for the crisis their friends in the City caused. They should expect the fight of their lives. Thousands of firefighters from across the country are joining the TUC's march for jobs and justice. Firefighters know first-hand that the Tory-led coalition cannot be trusted.