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
Andy Burnham is set to criticise those who question membership of international alliances and institutions in favour of 'isolationism'.
Wrestling legend Jimmy Snuka has been charged over the death of his girlfriend more than 30 years ago.
Rogue landlords are making life unbearable for tens of thousands of tenants in England, according to Shelter.