It’s a legal opinion rather than a ruling - the government then would produce an opposite argument in favour of allowing their spying on UK citizens and their forwarding data to allow the US to target drone strikes onto foreign civilians, managed from RAF bases - a judge would look at each legal opinion and then produce a ruling in a judicial review. I’d be surprised if the UK would prosecute its GCHQ staff, to say the least. It’s rare for the police to be prosecuted when they gun down unarmed UK citizens on the street in error - the prosecution is only under health and safety law and results in a fine
“Top lawyer opines that GCHQ spying is illegal & UK spies who help US drone strikes may be accessories to murder”
