Legal Liability

Legal liability means legal responsibility for harm or damage caused by a product or system. If you are injured or your property is damaged, a person or organisation must answer for it in law and may have to pay compensation. A program cannot be taken to court, so responsibility falls on the people or businesses behind the system, never on the software itself.

Why it can be unclear

An autonomous system can behave in a way that nobody directly chose at the moment the harm happened, and several parties are involved in getting it there:

• Designer — decided what the system should do and what it should ignore.
• Programmer — wrote the code that turns the design into instructions.
• Manufacturer — built the product, tested it and put it on sale.
• Operator — set the system up and chose to run it.
• Owner — the person or business that owns the system and keeps it maintained.

For example, a robot lawnmower runs over a child's foot. Was the sensor range set too short by the designer? Did the programmer fail to handle a child running in from the side? Did the manufacturer fit a cheap sensor? Or did the owner ignore an instruction to keep people away while it ran? Each answer points at a different party, so a court may have to decide where responsibility lies.

Duty of care and consumer rights

Manufacturers have a duty of care to customers: they must make sure products are safe and fit for purpose, meaning they do the job they are sold to do. Consumer protection law gives customers rights, so if a product is unsafe or faulty the buyer can claim a refund, repair or compensation from the seller without having to prove exactly which component or line of code was at fault. That pushes responsibility towards the business that sold the product, which is in a better position to test it and to insure against harm. These rules were written for products a person controls directly, so as autonomous systems spread, the law on liability may need updating.