Yes, the term "[un]constitutional" can be used in this way. You don't have to have a written constitution to be able to discuss constitutionality. The UK has no

Yes, the term "[un]constitutional" can be used in this way. You don't have to have a written constitution to be able to discuss constitutionality. The UK has no written constitution but we have experts in constitutional law. The problem with the title is that it is heavily editorialised. Not only does the article not use the term "unconstitutional", it doesn't even firmly conclude that the proposed law is contrary to the EU treaties. It outlines an argument to that effect and ends by stating further steps needed to make a strong case. The article itself has a perfectly good title: "Does monitoring your phone affect the essence of privacy?"