Image caption Chief Stamper has become a critic of US police tactics and culture

Police across the US have been criticised for their actions in clashes with Occupy Wall Street protesters. The man who led the police response to the Battle in Seattle protests at the 1999 WTO meeting blames the post-9/11 militarisation of American policing.

"Law enforcement across the country is pursuing the same tactics that failed so miserably in Seattle," Norm Stamper tells BBC World Service's Witness programme.

"There's a lack of patience, there's a lack of imagination and there are clear over-reactions to the challenges the police perceive. It is all so disheartening."

In November 1999, Chief Stamper was one of the main officials charged with managing the huge numbers of demonstrators who brought the city to a standstill in protests against the launch of a new round of global trade talks.

An estimated 50,000 activists from around the world flooded Seattle and occupied strategic crossroads, blocking delegates' access to the convention centre where the talks were to be held.

The demonstrations seriously disrupted the trade talks. The opening ceremony had to be cancelled because most delegates were unable to get to the meetings, and even US Secretary of State Madeleine Albright was stuck in her hotel room unable to give the speech she had prepared.

The police responded by spraying the crowd with tear gas, That, says Chief Stamper, set the tone for the next three days.

'Rocks, bottles, urine'

"After the tear gas, many previously non-violent demonstrators turned much more active, much more militant and in some cases violent in response to the violence they experienced," he recalls.

"We began getting major outbreaks of property damage and physical violence against the police officers, rocks, bottles and even human urine shot from high powered squirt guns.

"We saw what looked and felt very much like a war zone over the next three days and in effect we started it."

Media playback is unsupported on your device Media caption Police use of pepper spray on peaceful protesters in Davis, California provoked outrage

The National Guard soldiers were deployed to restore order, and authorities imposed a curfew.

They and the city police were widely criticised for the heavy handed tactics. Police use of tear gas was blamed for escalating the violence.

A few days later Chief Stamper resigned, but for many years he remained unrepentant.

'Military mindset'

After a great deal of soul searching and reflection, he gradually came to the conclusion that tear gas should never have been used against non-violent protestors.

Image caption Chief Stamper says the decision to use tear gas in Seattle set the tone for the next three days of protests

"The cop in me had made that decision not to step in and stop it," he says. "But as police chief, I should have done precisely that, and I will regret forever that I didn't do it."

Chief Stamper says he has learnt his lesson but that other US police forces have not. He blames what he calls the militarisation of the police in America.

In the years following 9/11, the federal government provided military equipment to police forces across the country and instilled in them a military mindset, all in the name of homeland security, the former police chief says.

Police today have lost sight of their purpose Norm Stamper, Former Seattle police chief

"The intentions are easily understood but it was a hopelessly misguided policy," he says.

"What we see now is even the tiniest rural police department dressed out in battle fatigues and Swat uniforms, sometimes driving armoured personal vehicles and making every marijuana bust a military operation."

One of the main tactics to which Chief Stamper objects is the use of chemical agents.

'50/50 partnership'

"It is clearly an abuse of tear gas when it is used against passive demonstrators who are taking part in acts of civil disobedience which are such a rich part of our democracy," he says.

Image caption In Los Angeles and elsewhere, police wearing riot gear have confronted demonstrators

"Today it is being used indiscriminately and that is really appalling."

The former police chief acknowledges that the Occupy protests in cities across America present a huge challenge to policing, but he says police need patience. And they need to sit down with demonstrators and negotiate.

"Law enforcement and community should be working together in a 50/50 partnership," he says.

Image caption Chief Stamper, shown in 1999 with Seattle Mayor Paul Schell, resigned after the WTO meeting

"We should recognise that we are a tool of community in the advancement of public safety and good. Police today have lost sight of their purpose."

Chloe Hadjimatheou's interview with Norm Stamper will be broadcast on BBC World Service Witness. You can download a podcast of the programme or browse the archive.

Norm Stamper is the author of Breaking Rank: A Top Cop's Expose of the Dark Side of American Policing.