The Sunday Times November 26, 2006
Word on the street ... theyre listening
POLICE and councils are considering monitoring conversations in the
street using high-powered microphones attached to CCTV cameras,
write Steven Swinford and Nicola Smith.
The microphones can detect conversations 100 yards away and record
aggressive exchanges before they become violent.
The devices are used at 300 sites in Holland and police, councils
and transport officials in London have shown an interest in
installing them before the 2012 Olympics.
The interest in the equipment comes amid growing concern that
Britain is becoming a surveillance society. It was recently
highlighted that there are more than 4.2m CCTV cameras, with the
average person being filmed more than 300 times a day. The addition
of microphones would take surveillance into uncharted
territory.
The Association of Chief Police Officers has warned that a full
public debate over the microphones impact on privacy will be
needed before they can be introduced.
The equipment can pick up aggressive tones on the basis of 12
factors, including decibel level, pitch and the speed at which
words are spoken. Background noise is filtered out, enabling the
camera to focus on specific conversations in public places.
If the aggressive behaviour continues, police can intervene before
an incident escalates. Privacy laws in Holland limit the recording
of sound to short bursts. Derek van der Vorst, director of Sound
Intelligence, the company that created the technology, said: It is
technically capable of being live 24 hours a day and recording 24
hours a day. It really depends on the privacy laws in a particular
country.
Last month Martin Nanninga of VCS Observation, the Dutch company
marketing the technology, gave a presentation to officials from
Transport for London, the Metropolitan police and the City of
London police about the CCTV system. Nanninga is to return next
year for further discussions.
There was a lot of interest in our system, especially with
security concerns about the Olympic Games in 2012. We told them
about both our intelligent control room and the aggression
detection system, Nanninga said.
In Holland more than 300 of the cameras have been fitted in
Groningen, Utrecht and Rotterdam. Locations include city centres,
benefit offices, jails, and even T-Mobile shops. The sensitivity of
the microphones is adjusted to suit the situation.
Police and local council officials are still assessing their impact
on crime, although in an initial six-week trial in Groningen last
year the cameras raised 70 genuine alarms, resulting in four
arrests.
Harry Hoetjer, head of surveillance at Groningen police
headquarters, recalled an incident where the camera had homed in on
a gang of four men who were about to attack a passer-by. We would
not normally have detected it as there was no camera directly
viewing it, he said.
Last Friday a Sunday Times reporter visited the office of Sound
Intelligence in Groningen to test the system. The reporter stood in
the control centre with a view of an empty room on one of a bank of
monitors. Van der Vorst entered the room, out of sight of the
camera, and began making aggressive noises.
The camera swivelled to film him and an alarm went off in the
control room, designed to alert police to a possible incident. The
cameras work on the principle that in an aggressive situation the
pitch goes up and the words are spoken faster, said van der Vorst.
The voice is not the normal flat tone, but vibrates. It is these
subtle changes that our audio cameras can pick up on.
Public prosecution services can use them in court as evidence. The
Dutch privacy board has already given its approval to the
system.
According to a spokesman for Richard Thomas, Britains information
commissioner, sound recorded by the cameras would be treated under
British law in the same way as CCTV footage. Under the
commissioners code of practice, audio can be recorded for the
detection, prevention of crime and apprehension and prosecution of
offenders. It cannot be used for recording private
conversations.
Graeme Gerrard, chairman of the chief police officers video and
CCTV working group, said: In the UK this is a new step. Clearly
there is somebody or something monitoring people speaking in the
street, and before we were to engage in that technology there would
be a number of legal obstacles.
We would need to have a debate as to whether or not this is
something the public think would be a reasonable use of the
technology. The other issue is around the capacity of the police
service to deal with this.