Thermal Imaging

With the increased use of thermal imaging cameras, an Englishman's home may no longer be the impenetrable castle it was. Ray Purdy explains
· legal implications of new methods of surveillance
· the Regulation of Investigatory Powers Act 2000
Police in Haringey, North London, have just begun using a new high-tech weapon to catch cannabis growers
in residential properties. Two properties have already been raided after a thermal imaging camera detected
extreme heat emissions coming from cannabis grow lamps (see The Times, 24 March 2006). Properties
where such lamps are used, release up to 10 times more heat than normal, or in the words of one senior police officer, "skunk houses can glow like a kid in a Ready Brek advert".
These new hand-held thermal imaging cameras are currently being piloted by the Metropolitan Police. Similar thermal camera technology has been used on police helicopters for a number of years, mainly to detect
suspects fleeing scenes of crimes, although they have also been used to detect heat from cannabis growing
in properties in Deptford (see BBC website, 6 February 2006) and Glasgow (see The Scotsman, 29 November 2005). The Metropolitan Police website notes that "this type of technology is the way forward for the Met
and will ensure that we stay one step ahead of the criminals and drug dealers".
The benefits to the police are obvious, but there has been less discussion of the legal implications of these
new methods of surveillance. Can the police freely use new technologies to look inside homes without check?
Are there major differences with thermal imaging compared to other forms of police surveillance? The issue
of what legal protection cannabis growers are entitled to expect on one side and the extent public interest
exceptions qualifying privacy rights can be invoked by the police on the other, could be coming to a courtroom near you.
Interference with private life
Article 8 of the European Convention on Human Rights (the Convention) provides that "everyone has the
right to respect for his private and family life, his home and his correspondence". The scope of such privacy
rights are difficult to define, but the courts tend to examine the level of intrusiveness. Case law suggests that
any intrusion should be more than slight and foreseeable.Page 2
Arguably, information collected by thermal imaging is unobtrusive because it is collected from outside, and it
is slight as it concerns only heat emissions. Conversely, anything that penetrates through the walls of a
home and reveals private activities within does not respect a person's private life. Privacy is by nature a subjective concept; while some may find thermal scans unobtrusive, others may find them invasive. The burden
of proof is on the aggrieved to establish the fact of interference and how it has threatened the effective enjoyment of his rights.
If the use of a thermal camera is shown to be sufficiently intrusive to interfere with a person's private life, a
court will examine whether the measure was in accordance with the law. Specific statutory authorisation is
required under Art 8(2) so individuals know with sufficient certainty where they stand. The question whether
an interference with a right is "in accordance with the law" has been a prominent issue in other surveillance
cases.
RIPA 2000
There is no specific UK legislation that expressly authorises using thermal cameras, although the Regulation
of Investigatory Powers Act 2000 (RIPA 2000) provides a comprehensive set of powers for police surveillance. RIPA 2000 was enacted to ensure that investigatory powers were used in accordance with human
rights.
The question of law is whether the statutory authorisation should expressly cover the type of technology
rather than merely providing a general power of surveillance. In this context it is noteworthy that television
licence surveillance is specifically authorised under RIPA 2000, s 26(6). Television licence surveillance is
clearly similar to using thermal cameras, taking place outside a property to determine an activity within a
residence. Thermal imaging has no such specific authorisation suggesting the legality could be vulnerable on
this score (see Malone v UK (1984) 7 EHRR 14).
Legitimate and proportionate aim
Even if a court is satisfied that the interference is in accordance with the law, it must still examine whether
the surveillance is compatible with the legitimate aims in Art 8(2). Public authorities are supposed to seek an
authorisation under RIPA 2000 for "directed surveillance" or "intrusive surveillance" if there is a possibility
that such surveillance could interfere with privacy rights (see Home Office, Covert Surveillance Code of Practice). Failure to obtain an authorisation under RIPA 2000 may be incompatible with the Human Rights Act
1998.
It is not known whether the police have sought authorisation under RIPA 2000 for thermal camera surveillance and whether they have classified it as either directed or intrusive surveillance. Before authorisation is
granted, it must be shown that in the circumstances of the case, it is in the interest of national security, for
the purpose of preventing or detecting serious crime, or in the economic well-being of the UK. These mirror
the legitimate aims contained in Art 8(2).
If seen to be a legitimate aim, the authorising officer must also believe that the surveillance is necessary and
proportionate to what it seeks to achieve. This decision is based on information contained in the application,
which includes:
· the reasons why the surveillance is considered proportionate;
· the nature of the surveillance;
· the identities, where known, of those subject to the surveillance;
· details of any potential collateral intrusion;
· and why the intrusion is justified.Page 3
Applications for intrusive surveillance go further, in that they must also contain information on the actual
residential premises where the surveillance will take place.
In deciding whether an authorisation is necessary and proportionate, there should be some balancing between the activity's intrusiveness on the target and others who might be affected by it, against the need for
the activity in operational terms. What seems crucial is how the thermal camera is used. If used to check a
specific house where cannabis is suspected of growing this could be necessary and proportionate, although,
if the police reasonably suspected such activities were taking place, then using a thermal camera might be
redundant as they could get a search warrant.
In Haringey, officers "have been patrolling the borough" using thermal cameras. This suggests the police
have been using them to monitor criminal activity over a wide area of random properties, rather than investigating specific properties (or streets where patrolling officers "smelt" cannabis but could not locate where
from).
Authorisations for both intrusive and directed surveillance are supposed to contain details of the identities
(where known) of those subject to surveillance. Applications for intrusive surveillance must also contain information on specific properties where surveillance will occur. It is therefore harder to justify surveillance operations where large-scale random surveillance is used.
Home Office statistics record 1,960 cannabis production offences in 2000, of which 243 people were jailed
(see Joseph Rowntree Foundation, A Growing Market: The Domestic Cultivation of Cannabis, 2003). The
2001 UK census revealed that there were approximately 23 million households in the UK. The key question
is therefore whether it is proportionate to undertake criminal surveillance measures that are possibly intrusive
on a wide number of householders to locate small numbers of cannabis growers?
US experience
Police use of thermal cameras has resulted in many contentious court cases in other jurisdictions. In 2001,
the US Supreme Court ruled in Kyllo v United States No. 99-8508 533 US 27 (2001) that the police use of a
thermal camera to detect cannabis grow lamps inside a private residence was an illegal, warrantless search
under the Fourth Amendment.
The Supreme Court, in a five to four decision, found it was unlawful because it went beyond what the police
could see in plain view from the house's exterior and provided information concerning the house's interior
that they would not have been able to obtain without going inside. It rejected the government's arguments
that the device did not provide significant detail regarding activities inside Mr Kyllo's home, and was not a
search as it only passively detected heat on exterior surfaces.
Justice Scalia observed that thermal imaging could potentially reveal intimate details, such as when the
householder was taking a bath. While the majority of judges considered the sensitive information gathered to
be slight, they found that because it was information about the home's interior, it was sufficiently intimate to
warrant legal protection. The legacy of Kyllo v United States is that the US judiciary has ended the police use
of thermal cameras without a search warrant supported by probable cause.
Canada's approach
The Supreme Court of Canada reached a different conclusion in R v Tessling [2004] 3 SCR 432. The court
unanimously held that using a thermal camera on a residence suspected of growing cannabis without a
search warrant did not constitute a breach of the accused's reasonable expectation of privacy under the Canadian Charter of Rights and Freedoms.
The court considered that the thermal camera only generated information about the house, whereas the
charter protected people not places. Consequently, patterns of heat distribution on the external surfaces of a
house were not the type of information to which the accused had a reasonable expectation of privacy. ThePage 4
judges concluded that information gathered on the heat distribution offered no insight into the respondent's
private life and its disclosure scarcely affected his "dignity, integrity and autonomy".
Nothing to hide, nothing to fear?
To those who consider that those with nothing to hide have nothing to fear, using thermal cameras to detect
cannabis growers and other criminal activity is hardly contentious. Others will consider such mass police
surveillance to be one more step towards an intrusive and totalitarian state.
It is arguable whether thermal cameras are sufficiently intrusive to interfere with a person's private life under
human rights legislation, but it is possible that such principles might be raised in the UK courts. The fact that
the US and Canadian supreme courts reached different conclusions illustrates the difficulty courts have in
resolving the tension between individual privacy and police use of new crime technologies. It is difficult to
predict which approach the UK judiciary may adopt--both approaches have their merits and reflect the complicated and subjective nature of privacy rights.
There are also wider complex legal issues concerning new technologies. Although there is potential protection from state surveillance, it is conceivable that the public could purchase and use thermal imaging themselves to monitor private houses. This could be for sales purposes, such as gathering information about
housing insulation, or even used by criminals to identify if a homeowner is at home or to detect rival drug
gangs. There appears to be no legislation controlling the sale of such equipment and privacy protection is
ineffectual where you are unaware your property is being monitored.
Balancing state intrusion
While individuals cannot expect to be left alone by the state completely, there are real and competing issues
relating to the balance of state intrusion. Public acceptance of new surveillance devices will be increasingly
important, particularly if the police are undertaking random thermal monitoring. Questions may also be raised
over who decides what technologies are allowed to be used for criminal detection and how these should be
used? The police's outlook on proportionality and necessity will differ from the man on the street. Who currently scrutinises the use of surveillance technologies? The courts are notoriously unwilling to elaborate general statements of privacy rights.
RIPA 2000 established the Independent Powers Tribunal which can investigate complaints about surveillance operations. However, as the majority of the public won't even know they are being monitored in this
way, this has limited effect as well. It seems that such privacy arguments will undoubtedly be bounced back
to the courts again soon.​