In the winter of 2010, police in London faced multiple violent protests.

While some of the protesters were peacefully opposing the British government's decision to raise college tuitions fees, others were motivated by a desire for disorder.

On November 10th 2010, tensions escalated when protesters attacked the headquarters of Britain's Conservative Party, destroying its lobby and using the building's roof to throw objects down at the police. In the aftermath of that incident, and with future protests already planned, the police adapted their operational plans.

They determined more officers would be needed next time around and that more aggressive tactics would be necessary. And that approach paid dividends in early December, when rioters armed with metal bars fought police near Parliament. While Prince Charles' motorcade was attacked, the protests were largely contained and controlled.

London's experience offers important lessons for U.S. police forces as they face the growing challenge of violent Antifa protesters. Here are the three key takeaways.

1) Plan in advance

As in Charlottesville and in Berkeley, local police forces will struggle if they are inadequately prepared for disorder. While dealing with large protest crowds is always difficult, intelligence-led operations to identify key organizers, plans and threats is crucial. And when the protest actually begins, it's important to have undercover police officers moving with the crowd so as to identify key troublemakers. It's also necessary to have enough police officers on the protest line so that the crowd can be controlled as needed.

Of course, such operational capabilities don't come cheap. They require overtime payments, close collaboration between federal, state and local law enforcement agencies, and the redirection of police resources away from other duties.

Nevertheless, government has a sacred duty to ensure that citizens can peacefully assemble and express their viewpoints. Claiming that intensive policing of protests is "too expensive" is a poor excuse.

2) Seize and retain the initiative

Again, as in Charlottesville and Berkeley, too often the police stand by as protesters wreak havoc. This acquiescence poses an unacceptable risk of damage to persons and property, and fuels the mob mentality of the crowd. If violent individuals believe they can be aggressive without repudiation, they will keep doing so and others will be inspired to join them (hence the term mob mentality).

Of course, a balance has to be struck between dealing with violent protesters and avoiding action that might inflame others to violence. Police "snatch squads" are one solution. These units involve specifically trained officers who can infiltrate a crowd and rapidly remove ringleaders.

In the worse case, however; if a large crowd is resorting to violence en masse, more robust action is needed. One option is "kettling" or the use of riot police charges to push protesters into an area where they can be more easily controlled. Such action represents an obvious escalation of police tactics, but sometimes it's the only way to deal with a situation that is spiraling out of control. One technique here, the utility of which was proved during the 2010 London riots, is the use of riot horses to break the mob's resolution and corral its participants.

Some would say that this is police brutality, but the police cannot yield order to thugs in black masks.

3) Detain and charge ringleaders

In the aftermath of any riot, it's crucial to identify, detain, and charge any individuals who have engaged in criminal violence. Because many of those who engage in low-level violent disorder are otherwise law abiding, the impact of a conviction can deter future violence and discourage others from making the same mistake. Staging evidence collection teams, such as the police officer below, at riots is thus crucial.

A further strength of post-protest policing is its assistance in identifying the most committed of violent protesters. If the police know who is a regular troublemaker, they can take preemptive action to prevent that individual from traveling to future protests. If nothing else, they can know whom to monitor closely on the day of.

Ultimately, as we struggle with groups like Antifa, we must be willing to learn from our mistakes and refine our tactics. If we don't, the scenes that have plagued over TV screens over the past few weeks will become the norm.