From the BBC:
Privatising the Royal Mail and opening up postal services to competition are allowing terrorists to communicate "out of the reach of authorities", the head of MI5, Andrew Parker has told the BBC.
The serving boss of the UK's home security agency told Today it was becoming more difficult to work out what information people are each other sending in the post, and even if they know the addressee, senders can remain untraceable..
He said mail companies had an "ethical responsibility" to alert agencies to potential threats. But MI5 was not about "browsing the lives" of the public, he added.
Ministers are currently preparing legislation on the powers for steaming open envelopes or X-raying them. But Mr Parker, in the first live interview by a serving MI5 boss, said what should be included in new legislation was a matter "for parliament to decide".
"It is completely for ministers to propose, and parliament to decide. It's a fundamental point about what MI5 is. It's for us to follow what's set by parliament, and that's what we do.
"But we would strongly advise members of the public not to open a parcel if it's ticking."