Is GCHQ's mass surveillance legal? No, according to legal advice provided to the UK Parliament's all-party parliamentary group on drones:
The advice warns that Britain's principal surveillance law is too vague and is almost certainly being interpreted to allow the agency to conduct surveillance that flouts privacy safeguards set out in the European convention on human rights (ECHR).
The inadequacies, it says, have created a situation where GCHQ staff are potentially able to rely "on the gaps in the current statutory framework to commit serious crime with impunity".
At its most extreme, the advice raises issues about the possible vulnerability of staff at GCHQ if it could be proved that intelligence used for US drone strikes against "non-combatants" had been passed on or supplied by the British before being used in a missile attack.
"An individual involved in passing that information is likely to be an accessory to murder. It is well arguable, on a variety of different bases, that the government is obliged to take reasonable steps to investigate that possibility," the advice says.
There's more, and its pretty damning. But this being the UK, the government will no doubt announce a whitewash "inquiry" then demand that the public "move on", while government lawbreaking continues unabated.
Meanwhile, that final point about passing on information used in drone strikes also potentially applies to New Zealand. We have a right to life in New Zealand, which all branches of our government must respect. Passing information to a foreign power which will be used to kill non-combatants breaches that right, and cannot be claimed to be a "justified limitation". And we know its happened - Nicky Hager's Other People's Wars reported that GCSB staff were posted to Afghanistan and walked into positions in the US headquarters, plotting targets for US drones to kill. That makes them accessories to those killings. Those drone strikes BTW are increasingly being regarded as war crimes for their indiscriminate targeting of civilians; GCSB co-operation with the NSA has exposed our government to complicity in those crimes.