Since the UK public seems mildly miffed with the whole GHCQ more than the US public about the NSA, the professional politicians are trying to officially distance themselves from the scandal in the eyes of the public *pause for jokes about stupidity of the general popularce*.
Personally, I am not sure if they are actually lying this time. It is not completely impossible that the scope details were something they were kept in the dark for just for such an occasion; plausible deniability and all that.
Naturally, if that is actually true, then the security apparatus has officially taken over UK. Glory be to Altana that the US remains clear of such a taint.