Computer, smartphone and network hacking by UK intelligence agency GCHQ is legal, a security tribunal has said.

The Investigatory Powers Tribunal ruled on Friday that computer network exploitation (CNE) – which can include remotely activating microphones and cameras on electronic devices such as iPhones without the owner’s knowledge – is legal.

The case, which was heard in 2015, was the first time that GCHQ admitted to carrying out hacking in the UK and overseas. Previously, their policy had been to “neither confirm nor deny”.
During proceedings, GCHQ admitted that it carries out CNE outside the UK, and that in 2013 about a fifth of its intelligence reports contained information derived from hacking.

Source: GCHQ hacking phones and computers is legal, says top UK court

So is there any kind of warrant procedure at all before they start hacking private individual or business computers?