After Obama’s proposals to introduce a $75 Million scheme to assist police agencies with purchasing body worn video cameras, civil rights activists and some police chiefs are warning that firm rules on how to use the equipment must also be introduced.

Without proper oversight to address potential misuse, the wide deployment of the equipment could undermine efforts to build trust between police and communities across the country.

Obama's plan, which requires congressional approval, calls for departments to undergo training, receive guidance on best practices from the Department of Justice, and submit a plan of use for approval.

In flurry of high-profile fatalities across the media in recent months the calls for firm guidance/policy on the use of body worn video have come forward.

"You must have an accountability mechanism," said Barbara Arnwine, executive director of the Lawyers' Committee on Civil Rights. "If you have a department that has a bad record and is bad at following through on discipline, then body cameras are meaningless."

Body worn video cameras have surged in popularity in recent years, with many companies providing the wearable device and back-end video evidence management solutions. Reveal, operating globally from the UK has been established for over a decade, gaining experience in the world of body worn video since its infancy. In this time the technology of the world has grown at an expedited pace, often times with the development of technology outstripping policy.

In 2006 the Body Worn Video Steering Group (BWVSG) was established as an independent body to provide insight and create debate around the future of body worn video in the public and private sectors. Hosting a tri-annual series of talks, discussion and networking from various researchers (such as the popularly cited Rialto Study, co-authored by speaker Barack Ariel) and police professionals, it has become a go-to guide for agencies considering, testing and currently using body worn video cameras.

Additionally, the President’s proposal would be supported by a $263 million investment package for law enforcement agency training, resourcing for reform, and increasing the number of cities where Department of Justice facilitates engagement with local communities.

Police Chief Michael Chitwood, who has been using body cameras in his department in Daytona Beach, Florida, since 2010, said his experience has shown the need for strong oversight.

He said he fired an officer earlier this year for turning off his camera during a brutal beating of a woman, which violated a policy he had established.

Chitwood said the Justice Department should issue strong guidelines that could override local politics and union power that can tarnish policies.

"The Department of Justice has a huge role in it because different jurisdictions have different internal power structures. Any policy that a commissioner comes up with, that (police) union is going to use its power to stop the cameras unless they get the policy that they want," he said.

Not all police chiefs share his view. "I wouldn't want the federal government dictating how I use my cameras," said Ken Miller, police chief in Greenville, South Carolina, and formerly chief in Greensboro, North Carolina, where he used body cameras. "Every community has their own issues and their own dynamics."

It's also not clear how a federal enforcement mechanism could work. Grants to purchase equipment would be provided by the Justice Department's Office of Justice Programs, which has little authority beyond ensuring the specified equipment is purchased.

Reveal, who created and now sponsors the BWVSG, encourages the use of resources from its website as guidance, with examples of policy, large scale programme drafting, key studies, code of practice, and more. Hampshire Constabulary, whom Reveal has worked with for many years, was recently praised by Home Secretary Theresa May for its innovative use of body worn video in efforts to reduce crime.

Body cameras are used by thousands of police officers in the US alone, and are viewed as a tool to increase transparency, particularly in resolving discrepancies between an officer's account and a citizen's account of a violent interaction.

A report funded by the Justice Department and released earlier this year by the non-profit Police Executive Research Forum (PERF) found that of the 63 agencies that reported using body cameras, about one-third did not have a written policy for their usage.

Lindsay Miller, a PERF researcher who worked on the study, said she repeatedly heard from police chiefs that they did not know how to fairly implement their use. "It's not as easy as sticking a camera on an officer and sending them out on their way," Miller said.

Among the unresolved issues: whether cameras are allowed into private homes, how long footage should be stored and how much access the public should have to the footage.

There is early evidence that written policies make a difference. A study out of Arizona State University this year on the Mesa, Arizona, police department found that police officers were 20 percent more likely to turn on their cameras when responding to an incident when the department had a policy that required them to do so.

Finally, the decision to use body worn video is with a primary objective to document incidents and gain evidential material. It is therefore essential to have guidance for officers using the devices in addition to training that will ensure the benefits and capabilities of body worn video are maximized for full effectiveness as a crime-fighting tool.

For more information on the BWVSG visit here and follow on Twitter for regular updates.

(Additional reporting by Andy Sullivan and Richard Cowan; Editing by Karey Van Hall and Douglas Royalty)