On This Day: Thousands of anti-Vietnam protesters clash with police in London

October 27: Thousands of Vietnam War protesters clashed with police outside the U.S. Embassy in London on this day in 1968 in one of the biggest ever demonstrations in Britain.

The violence began when around 6,000 members of the a Maoist group broke away from an otherwise peaceful march involving up to 200,000 people.

Rioters - angered by American involvement in the war - filled Grosvenor Square, formed a human chain and charged at police in a bid to storm the U.S. consulate.

[On This Day: Ho Chi Minh dies]

Clashes continued for around three hours, with some of the violent protesters throwing stones, fireworks and other objects.

But the 1,000 officers on guard, who included mounted police, were able to hold back the rioters led by the Maoist Britain-Vietnam Solidarity Front.

A British Pathe newsreel shows the beginning of the march in Trafalgar Square, where peace activists, including actress Vanessa Redgrave, assembled.

[Vietnam War pair return home after 41 years in forest]

And the reporter claimed that among them were “trouble maker” and filmed those with bushy beards carrying anarchist and communist flags.

Then, in a smoke-filled Grosvenor Square, police were shown tacking to the ground and carrying away some protesters amid a hail of noise and firework missiles.

Some of the 117 policemen injured during the clashes were also filmed being stretchered away.

The rest of the march, which was organised by the Vietnam Solidarity Campaign, continued peacefully to Hyde Park.

Tariq Ali, the head of the VSC, handed in a 75,000-signature petition to 10 Downing Street to ask the government to stop supporting the U.S. in its war against Vietnam.

The wider demonstration was the sixth biggest ever held in Britain.

The largest was the 2003 Stop The War march in London, which attracted an estimated two million people who hoped to stop the impending invasion of Iraq.

This is followed by the 2002 anti-hunting ban demo (408,000), 1983 CND march (400,000), 2011 anti-cuts protest (400,000) and the 1981 CND rally (250,000).

But the October 1968 Vietnam War protest, which followed another in March of that year, was unprecedented in scale at the time.

[On This Day: Vietnam War ends]

The Cold War conflict, in which American troops supported capitalist South Vietnam against communist North Vietnam, was a highly divisive issue.

Britain’s Labour government had refused American appeals for troops, but at the same time did not publicly criticise U.S. involvement.

This contrasted with Canada, which refused to stop American military conscripts – or draft dodgers – from crossing the border and seeing permanent residence there.

By 1968, both the violence in the far-eastern country – triggered by a U.S. military surge - and protests across the globe were at their apex.

By the following year, American generals increasingly recognised that the war – in which the North was backed by Soviet supplies and cash – was unwinnable.

In 1973, the U.S., which lost 58,000 lives during the controversial conflict, pulled all its forces out in what was seen as a deeply humiliating exit.

The war, which led to the deaths of up to 3.1million people, ended on April 30, 1975 after the North seized Saigon, which is now known as Ho Chi Minh City.