It is indeed a constitutional principle in many EU countries.

It is also part of the Treaty of Lisbon via the EU Charter of Fundamental Rights, which is the closest thing to a constitutional level law for the EU.

Not that this has ever stopped anybody.

I think the issue lies with how do you define "privacy of communications is respected".

Because that would technically make any present day wiretap illegal too.

So the detail is written in normal law tract...