Sir Malcolm Rifkind has said that security chiefs speaking to MPs in public today was "an historic occasion" that will be repeated.
The Chair of the Intelligence and Security Committee added that he believed those involved were glad of the chance to speak publicly.
He said: "Many of them have been upset at the accusations that they have been doing something improper or doing something unreasonable to their fellow citizens.
"I suspect they were pleased to have the opportunity in public to speak about the work their own staff do and how important it is to the national interest."
More top news
The Prince of Wales' household is so riddled with infighting it is nicknamed Wolf Hall, according to a new unofficial autobiography.
There will be blustery showers across northern parts overnight with showery rain and sleet across the south.
Rap mogul Marion 'Suge' Knight has been arrested on murder charges after a fatal hit-and-run incident in Los Angeles.