The best way to tell a lie is to tell the truth in such a manner as your victim won't believe you.
That sounds almost exactly like something Sir Humphrey Appleby would say:
Bernard: I was just wondering, Minister, if we might not use the Rhodesia solution?
Humphrey: [beat] Bernard, you excel yourself! Of course, Minister, the Rhodesia solution!
Hacker: What are you talking about?
Humphrey: Oil sanctions, remember? A member of the government was told about the way British companies were sanction-busting.
Hacker: What did he do?
Bernard: He told the Prime Minister.
Hacker: What did he do?
Humphrey: He told the Prime Minister in such a way that the Prime Minister didn't hear him.
Hacker: What, d'you mean I should mumble it or something in the division lobby?
Humphrey: No, Minister, you write a note.
Hacker: In very faint pencil? Please, be practical.
Humphrey: No, Minister, it's awfully obvious; you write a note which is susceptible to misinterpretation.
Hacker: Oh, I see. "Dear Prime Minister, it has come to my attention that the Italian Red Terrorists are getting hold of British top secret bomb-making equipment" — how do you misinterpret that?
Humphrey: You can't.
Hacker: Well, exactly.
Humphrey: So you don't write that. You use a more circumspect style, and you avoid any mention of bombs or terrorists or any of that sort of thing.
Hacker: Wouldn't that be rather difficult? Is that what it's all about?
Humphrey: You say — Bernard, write this down — "My attention has been drawn, on a personal basis, to information which suggests the possibility of certain irregularities under Section..." [snaps fingers]
Bernard: Section 1 of the Import, Export and Customs Powers Defense Act 1939 C.
Humphrey: Thank you, Bernard. You then go on to suggest that somebody else should do something about it. "Prima facie evidence suggests that there could be a case for further investigation; to establish whether or not, inquiries should be put in hand." And then you smudge it all over. "Nevertheless, it should be stressed that available information is limited, and relevant facts could be difficult to establish with any degree of certainty."
Hacker: I see.
Humphrey: Then, if there were an inquiry, you'd be in the clear, and everybody would understand that the busy PM might not have grasped the full implications of such a letter.
Hacker: They certainly would; that's most unclear.
Humphrey: Thank you, Minister. Then you arrange for the letter to arrive at Number 10 on the day the PM leaves for an overseas summit, so there's also doubt about whether it was the PM or the acting PM who read the note. And so the whole thing is written off as a breakdown in communications, everybody's in the clear, and everybody can get on with their business.
Bernard: Including the Red Terrorists.
Humphrey: Exactly.