Baltimore police have been quietly spying on the city from above

A US city has exploded in anger over a police program after it was revealed the whole city was being watched.

THE US city of Baltimore has been secretly spying and recording the every move of its citizens from the sky above since January 2016.

Baltimore police, using money provided by a wealthy, anonymous donor, have been surveilling the city with a manned plane loaded with cameras that can view 48 square kilometres below.

The plane hangs above the city largely out of view from those on the ground and takes pictures of the city every second, beaming the footage back to a headquarters on the ground.

The company employed to carry out the mass surveillance is called Persistent Surveillance Systems and was profiled last year by news.com.au.

According to the company’s founder Ross McNutt who in 2004 worked for the Airforce Institute of Technology, the surveillance system was thought up in an attempt to help the war effort in Iraq which wasn’t looking good for the US at the time.

“The IEDs (improvised explosive device) were killing many of our troops and our commander asked that we see what we could do to help,” he told news.com.au in July 2015.

“We developed an idea that would allow us to track bombers back to the place they came from so we could then address the source of the bombs,” he said.

The idea proved immensely useful in capturing those planting IEDs and the air force has since spent more than $US1 billion ($A1.3 billion) to improve and enhance the system.

However the secret and sustained use of the program by Baltimore officials marks a dramatic change in how the US government is deploying the technology and was made public Wednesday AEST in an explosive report by BloombergBusinessweek.

Amazing cover for the upcoming edition of Bloomberg Businessweek: It's not spying if they're ALWAYS WATCHING. pic.twitter.com/1em0cYnE4e

— Sesil Fatima (@BmoreDoc) August 24, 2016

Despite the fact that it seems to have come as a major surprise to the unsuspecting residents of Baltimore, at a news conference on Wednesday local time, Police Department spokesman TJ Smith repeatedly insisted the test program — which has been running for nearly eight months — was not a secret.

“It’s not a secret spy plane,” Smith said as reporters pressed him for an explanation for the lack of information. “There’s no conspiracy to not disclose it.”

The test program lets the department evaluate the effectiveness of a potential tool in the department’s crime-fighting arsenal, he said.

Ostensibly, the aptly named Persistent Surveillance Systems is about preventing and prosecuting crimes and police have been successfully using it to that effect.

When a crime occurs, teams of analysts in the control room can simply scroll back in time to the scene of the incident and identify those involved. From that point, they can follow the target by clicking forward through the images to the present moment and pinpoint their location.

The plane fitted with cameras can encompass 48 square kms.

The future of Big Brother?

Baltimore has been a city plagued by a high crime rate in recent decades and, like many US cities, has been marred by protests and unrest recently in the wake of police killings of young African-American men.

McNutt has long been keen to snag a long-term contract with an American metropolitan police department and Baltimore seemed like the company’s best chance to date.

The Baltimore public has been unaware of the discreet arrangement between the city and the company which has actually frustrated McNutt. He believes his company’s service can reduce the crime rate by 20 per cent but doesn’t yet have the data to back it up. McNutt thinks the reduction in crime will be greater if the technology is used in a transparent way and the public is more widely aware of its use.

The US government has previously used Persistent Surveillance Systems to address the high crime rate in Dayton, Ohio.

After a five-day trial in June of 2012, the results proved exciting to law enforcement and the police chief recommended a permanent expansion of the services.

However the city decided to hold a public forum to debate the idea and only about 75 people turned up. Due to the high rates of crime, many were supportive of having the surveillance plane overhead. But others, a slightly smaller but very vocal group, were opposed and ultimately dissuaded the city from adopting the service.

Analysts are observed to ensure they are only tracking criminals.

According to Baltimore officials, the first phase of the Baltimore program included 100 hours of the plane flying over the city in January and February. The program is now in Phase 2, working toward 200 hours that began in mid-June. The second phase will end in a few weeks and the police department “doesn’t have a plan to move forward beyond that,” Smith said.

The American Civil Liberties Union of Maryland has expressed outrage at the program.

“The fact that the (police department) has been engaged in a secret program of mass surveillance is both incomprehensible and unacceptable,” David Rocah, senior staff attorney, said in a statement.

“The surveillance program itself is a privacy nightmare come to life and precisely what we have warned against for years,” Rocah continued.

The story by Bloomberg will no doubt reignite the debate about the trade off between civil freedoms and the lengths we should be willing to go to prevent crime.

But Mr McNutt said they had made assurances to allay such concerns.

“We have developed a whole host of privacy policies and procedures that protect people privacies. In addition we have designed the system to be limited to one pixel per person, which only allows us to barely see a person and track them to a car. We only support reported crime investigation and ongoing criminal investigations,” he said last year.

At Wednesday’s press conference Smith said Baltimore police “aren’t surveilling or tracking anyone. The only ones who should be concerned are criminals.”

-With AP