Following a test phase, German rail company Deutsche Bahn has announced plans to equip train station security personnel at trouble spots with body cameras or "bodycams". An interview with Oldenburg data protection experts Jürgen Taeger and Edgar Rose.

QUESTION: Mr Taeger, what exactly are bodycams?

TAEGER: Bodycams are cameras that are attached to clothing. The employees of DB Sicherheit, a Deutsche Bahn AG security subsidiary, wear them attached to the chest area of their uniforms and they have a screen on which anyone within the camera's range can see themselves when the camera is activated.

QUESTION: Bodycams are now to be added to the already vast amount of video surveillance technology DB uses at train stations and in trains. Why?

TAEGER: It's important to differentiate here: the fixed video cameras permanently installed at train stations were put there on the basis of Section 27 of the Federal Police Act. The video footage these cameras supply is stored and evaluated by the federal police. Incidentally, that also applies for footage from video cameras on trains. On the other hand DB Sicherheit is responsible for the footage from the bodycams. The company is using the video technology to protect its staff as well as its customers.

"Working for DB Sicherheit is a dangerous job"

ROSE: The motivation behind the move is understandable, because working for DB Sicherheit is a dangerous job. To quote a few figures: there were 1,207 cases of criminal assault against the company's 2,200 employees last year. In 92 of those cases the employees were left temporarily unable to work, meaning that these incidents counted as work-related accidents that had to be reported. And those figures are rising. This high-risk situation is the reason why Deutsche Bahn, as the employer, had to start looking for ways to better protect its employees.

QUESTION: Mr. Taeger, You are a member of the company's Data Privacy Advisory Board and were asked to compile a legal opinion. What was the basis for your opinion?

TAEGER: DB Sicherheit is not a police body so it doesn't have any authorisation arising from the Federal Police Act. Video recordings, however, contain personal data. Documenting and processing them is only permissible if you have the required authorisation. A legal basis for this authorisation is provided by Section 6b of the Federal Data Protection Act according to which video surveillance of public spaces is permitted under certain circumstances: to enforce domiciliary rights or safeguard legitimate interests for specified purposes. On the other hand you have the legitimate interests of those affected by such measures – in other words of persons who may be filmed by the camera. And obviously at train stations that's a large number of people: from innocent passers-by to troublemakers and known criminals. They all have fundamental rights – for example the right to informational self-determination or the right to protect their own image.

QUESTION: After weighing up the different interests you come to the conclusion that the use of bodycams is legal. Under what circumstances?

ROSE: First of all they should only be used in high-risk areas. So not at every village train station but where experience shows that there is a tendency for dangerous situations to arise. In the test phase Deutsch Bahn used body cameras only at Berlin's three major train stations, on regional and city trains travelling between those stations and at the main train station in Cologne during the carnival period.

TAEGER: Another prerequisite is transparency. Employees equipped with bodycams must wear a security vest that not only identifies them as DB Sicherheit employees but also reads "Video Surveillance" to notify customers. This, however, doesn't mean that the bodycam should already be switched on in such circumstances. We have defined a clear step-by-step protocol.

QUESTION: What does it look like?

ROSE: Our aim is for the situation to be defused before the camera is activated. We're talking about situations involving anything from vulgar behaviour and harassment of other passengers to attacks resulting in injuries. In such scenarios, simply wearing the security vest can be a first step towards de-escalation. If that doesn't work the disruptive person is addressed directly and informed that their actions will be filmed if they fail to comply with DB Sicherheit's requests. In the next step the employee activates the camera without actually filming.

"In some cases it provokes a very strong reaction"

QUESTION: So the person sees their image on the screen, like with a selfie. What effect does that have?

ROSE: In some cases it provokes a very strong reaction – we know this from interviews carried out with security personnel during the test phase. Some people raise their hands as if a gun were being pointed at them, or they run away. This shows what strong a deterrent it can be just to see yourself on the bodycam's screen. At the same time it highlights the intensity of the encroachment on personal rights. That's why there has to be a good reason, in this case a DB employee or passers-by finding themselves in a high-risk situation, as well as a concept for use strictly based on the principle of proportionality. The employees need to be very well trained so they can be relied on to react appropriately and on a step-by-step basis in such situations.

TAEGER: If the activation of the screen doesn't defuse the situation the camera is switched on properly – again only after the person in question has been informed.

QUESTION: What do DB staff who have used the cameras have to say about them?

ROSE: So far the response has been very positive, in particular as the results of the test phase are so impressive. Based on the same number of working hours, there were 30 cases of actual bodily harm during patrol rounds carried out without bodycams compared to just one case for rounds with staff wearing bodycams.

"Legal situation different when it comes to face recognition"

QUESTION: A change of topic: biometric face recognition is also currently the subject of intense debate. It has been tested at Berlin's Südkreuz train station on volunteers whose photos had been stored in the system in advance. What are your views on this development?

TAEGER: The legal situation is very different when it comes to face recognition. With these tests of a technology that is not yet fully developed, the German state has taken a first step. And that's what worries me: that further steps will follow and at some point we'll see the introduction of blanket video surveillance with face recognition in Germany. I, personally, don't want that, and it wouldn't be compatible with constitutional laws – either the laws of the EU Charter of Fundamental Rights or the laws of the German constitution. Even the planned trial at Südkreuz station is inadmissible from a legal point of view, particularly as the argument that the test subjects have given their consent doesn't legitimise the filming of other passers-by who are also scanned by the system.

QUESTION: How do you see this in connection with the legislators' recent changes to the identity card and passport laws?

TAEGER: You're talking about the new Section 25, Paragraph 2 of the Identity Card Act that came into effect in July. It has paved the way for centrally organised law enforcement agencies, i.e. the intelligence services and the police, to access the biometric passport photos in the electronic registers of local residents' registration offices. "In order to fulfil their tasks", so it states. Even tax investigation authorities are allowed to call up the photos and store them in a central database. It can even be done in connection with traffic offences.

"We do well to highlight the dangers at an early stage"

QUESTION: What do the security agencies do with this data? When are they allowed to use it and what for?

TAEGER: Good question. There has to be a concrete reason but they don't need a court order as they would to take someone into custody or search their home – both actions which also encroach on fundamental rights.

QUESTION: Are these the first steps in the direction of a Big Brother state?

TAEGER: As regards the face recognition technology currently being tested, it would indeed provide the material for blanket surveillance. This is not the reality now - we should see this development from the perspective of historical experience but observe and evaluate it extremely carefully. Consequently, we would do well to highlight the dangers at an early stage in order to counter the gradual development of surveillance measures that are incompatible with the constitution.