The Prime Minister has reasserted the rule that the security services cannot spy on MPs and confirmed that the same principle protects AMs and members of other devolved parliaments.
David Cameron's ruling follows a court case in July, when it emerged that GCHQ guidance had been revised and that AMs were no longer protected by the so-called 'Wilson Doctrine'.
It was named after the Labour Prime Minister Harold Wilson, who decided in 1966 that MPs could not be spied on. However, in a letter to the Assembly's Presiding Officer, Dame Rosemary Butler, Mr Cameron makes clear that he could give special permission in exceptional circumstances.
In a concession to the fact that policing is devolved in Scotland but not Wales, the Prime Minister adds that if the spying was to be carried out by Police Scotland, he wouldn't be consulted. It would be entirely up to the Scottish Government whether to over-ride the 'Wilson Doctrine'.