I think it’s a bit different because it’s M15 as the source rather than a leak or a journalist. But to be honest It doesn’t really matter. It seems that every where you glance in the Commons you will spot an odious twat. I assume if Gardiner had done anything demonstrably wrong or traitorous he’d be banged up already, and rightly so. I can’t be bothered to look up whether he’s been protecting Chinese interests on the floor of the house, although I’d assume that he (and his ilk) would never explicitly condemn Chinese human rights abuses because their values are seriously ****ed up.
I also can’t be bothered to look up who MI5 ultimately reports to - is it the Home Office, and MI6 the Foreign Office?