Supplementary memorandum submitted by
the Home Office
CRIME AND
SECURITY BILL—DNA
DATABASE
During the Second Reading debate on the Crime
and Security Bill, I undertook to write to colleagues recording
the main statistics concerning the use of the DNA database to
tackle crime and also to explain the research behind the Government's
retention proposals.
The retention of biometric data is understandably
an emotive issue. To promote the debate which I welcome, I thought
it would be helpful to lay out the facts which underpin our proposals.
Without DNA evidence, thousands of crimes would go unsolved and
many serious and dangerous criminals would be walking our streets.
Between 1998 and March 2009, DNA evidence helped to solve over
304,000 crimes. In 2008-09 there were 252 homicides and 580 rapes
with a DNA scene-subject match. In the same period, there were
detections in 70 homicide and 168 rape cases where a DNA match
was 0 available.
However, we have been careful to balance the
wider interests of public protection with the rights of the individual.
We have used the best evidence available to ensure that we only
retain DNA for as long as it is necessary in the interests of
public protection.
NEW RESEARCH
Much has been made of the Scottish retention
system, although that system, in effect, allows for indefinite
retention of DNA profiles of those arrested but not convicted
of serious offences. By contrast, our proposals would be an automatic
deletion after six years for adults arrested for any offence and
after three years for children, unless they are 16-17 year olds
arrested for serious offences when profiles will be retained for
six years. Like the Scottish system, we are seeking a balance
between the rights of individuals who have been arrested but not
convicted of a crime with the need to protect the public. However,
in striking that balance we have used the best evidence available;
specifically, research that was not available to the Scottish
Executive when they created their retention regime in 2007.
During the course of the consultation on the
DNA database that we published in May 2009, we undertook further
research. We would ideally like to know the likelihood that an
individual arrested but not convicted is subsequently convicted
of an offence. The data available to us, however, describe the
likelihood of subsequent arrest, not conviction. An arrest is
not proof of guilt, but data on arrest provide an indication of
the risk of subsequent offending, compared with the risk present
in the general population.
We had a maximum of three years of usable PNC
data on arrests available to us, because of weeding of PNC arrest
entries for earlier years. As a result, we had to extend the data
statistically to forecast the risk of re-arrest. On this basis,
we estimated that the risk of re-arrest in the group originally
arrested but not convicted remains higher than in the general
population for six years after the initial arrest, providing a
justification for our retention policy.
It has been suggested that the research carried
out into the Scottish system (by Professor Fraser) did not uncover
any evidence to suggest that the Scottish approach to retention
had caused any detriment to the detection of serious crime there.
However, that is to misunderstand this research which did not
assess whether alternative systems would have been more effective.
It was also unable to review how many serious crimes went undetected
as the relevant DNA profiles had been deleted and, therefore,
was not in a position to conclude whether there was any detriment
to the detection of serious crime.
DNA RETENTION FOR
THOSE ARRESTED
FOR LESS
SERIOUS CRIMES
Criminological opinion tells us that the seriousness
of the initial offence for which the person was arrested is not
a good indicator of the seriousness of any subsequent offending.
This has been confirmed by our latest research.
In 2008-09 alone, the ACPO Criminal Records
Office found that 79 rape, murder or manslaughter cases in England
and Wales were matched to the DNA database from DNA profiles that
belonged to individuals who had been arrested but not convicted
of any crime. Of that number, 36 cases were found to have had
a direct and specific value to the investigation. If we were to
have applied the Scottish model's retention regime to this number
and only retained for three years the profiles of those who were
arrested but not convicted of a serious crime, then the number
of potential detections would have reduced by almost two thirds
to just 13 detections. In short, 23 victims of the most serious
crimes and their families could have been denied justice last
year alone under the Scottish model.
DNA SAMPLES
On DNA samples we are taking a more liberal
approach than currently adopted in Scotland. A DNA sample contains
a person's biological tissue. This is different to a DNA profile,
which consists of 10 pairs of numbers (and an X or Y marker to
indicate sex). It is much more intrusive to retain a DNA sample
than to retain a DNA profile.
We propose to destroy all DNA samples within
six months of collection, even for those who have been convicted.
The Scottish model retains all DNA samples for at least 20 years
for all those convicted and, in line with DNA profiles, potentially
indefinitely for those arrested but not convicted of a serious
crime.
I look forward to an informed debate as the
Bill progresses through the House.
February 2010
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