If I implement some software that is illegal (for example, for something as small as sending unsolicited email, or something as big as a deliberate bug that would cause a death), at the request of a client, am I legally liable for it?

Does it make a difference whether or not I know the law, and have explained it to the client?

I'm a freelancer in the UK.

(Out of interest: I'm not trying to get around the law, but trying persuade my client to stick to the law).

  • The TL;DR; answer is that I was only following orders was ruled as an invalid defence at Nuremberg, and I wouldn't rely on it today. Equally ignorance of the law is no defence wither.
    – Andrew
    Commented Jan 29, 2014 at 19:11
  • 1
    Related about doing iffy things: freelancing.stackexchange.com/questions/1095/…
    – Canadian Luke
    Commented Jan 30, 2014 at 0:00

4 Answers 4


I am a developer and in the past have had to tell clients that I would not do something because it was illegal. A perfect example of this would be embedding copyrighted images or fonts on a webpage without a license.

Remember when Megaupload was busted they even arrested the graphic designer. None of those detained were US citizens, but since the domain name and/or servers were from the US they were still considered to be under FBI jurisdiction.

As far as sending unsolicited email, it is illegal in the UK as well as just about everywhere else in the world: http://en.wikipedia.org/wiki/Privacy_and_Electronic_Communications_%28EC_Directive%29_Regulations_2003

They say ignorance is no excuse for breaking the law (Ignorantia juris non excusat), but this is more of a legal principle than a "law". However I would assume if you are not aware of the infraction you can still be held liable in the UK. But I suppose that holds true for your boss as well.

But in the end I think to truly answer this question you would need to talk to a lawyer, and to tell him/her specific details of the possible infraction.

  • Keep in mind that for a lot of things, the standard is "knew or should have known." There's a difference between "was willfully ignorant of" and "had no way of knowing that" and that is a meaningful distinction. Commented Feb 7, 2014 at 3:45

I don't think this can be answered in generalities. It depends to a large extent what is going on, what the nature of the conduct is, etc. In general, if in doubt, ask a lawyer. I could imagine cases where it might come out either way.

In general if something is illegal and/or harmful, and you know this, you shouldn't implement it whether or not you are liable. If things go badly, you may be adversely affected and even if it doesn't cost you money it will cost you some of your hard-earned reputation. There may be exceptions to this rule but it is almost always a good starting point. You don't want to be associated with failures, particularly failures that make the news, and in some cases, this could lead to liability on your part.


Since this is a legal issue, it is very smart to consult a legal counselor, Paying him 1 hour work advise will save you a lot of money.

Now, to reply how I see this, in case you want to risk your money.

If you are a company or a registered individual, and the client comes to your business and you implement illegal app, you are legally responsible.

If you are his full-time employee and among other tasks he gives you a task to create such software, then you are not legally responsible.

Now you probably know it's smart to stay away from such project. If you really want it since the money is good, then get a contract where the project will look like a legal thing (collecting emails can be legally used in statistics as well) and put the clause where you are not reliable if the client uses the product for illegal matters. Then it's his responsibility to use it legally or not.

But to repeat again, get a professional advise in written from the legal counsel. This money will be well spent money.


Here's a parallel. You work in a store. A friend wants to pay you to leave the back door open when you close up the store at night, so he can burglarize it. If you go through with it, who ends up in jail?

  • 1
    Hi codenoire, it's important that we make sure that answers posted fully answer the question. Our goal is to become a strong resource for knowledge, backed with facts, references, and specific expertise. I'll leave this here for a bit in case you want to expand with an edit. Good luck.
    – jmort253
    Commented Jan 29, 2014 at 5:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.